Title Page
 Table of Contents
 Secretary's report
 Report of the acting treasurer
 Program of the third annual...
 Committees for the third annual...
 The achievement medal, research...
 Notes on the sharks of Florida
 Variations within successive categories...
 Hitherto unrecorded vertebrate...
 Additions to the recorded pleistocene...
 The role of hormones in the development...
 Torreya west of the Apalachicola...
 A physiographic study of the tree...
 Pretended accuracies in comput...
 The necessity for artesian water...
 Notes on Florida water snakes
 Notes on the feeding and egg-laying...
 A preliminary report on studies...
 Are women clairvoyant?
 Ovulation time in primates
 Holothurians from Biscayne Bay,...
 Academy personnel

Title: Proceedings of the Florida Academy of Sciences
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00001490/00003
 Material Information
Title: Proceedings of the Florida Academy of Sciences
Abbreviated Title: Proc. Fla. Acad. Sci.
Physical Description: 7 v. : ; 23 cm.
Language: English
Creator: Florida Academy of Sciences
Publisher: Rose Printing Co., etc.
Place of Publication: Tallahassee
Frequency: annual
Subject: Science -- Periodicals   ( lcsh )
Genre: periodical   ( marcgt )
Dates or Sequential Designation: v. 1-7; 1936-44.
 Record Information
Bibliographic ID: UF00001490
Volume ID: VID00003
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 001745383
oclc - 01385276
notis - AJF8161
lccn - sn 85003387
issn - 0097-0581
 Related Items
Succeeded by: Quarterly journal of the Florida Academy of Sciences

Table of Contents
    Title Page
        Page i
        Page ii
    Table of Contents
        Page iii
        Page iv
    Secretary's report
        Page 1
        Page 2
    Report of the acting treasurer
        Page 3
    Program of the third annual meeting
        Page 4
        Page 5
        Page 6
    Committees for the third annual meeting
        Page 7
    The achievement medal, research grant, and changes in the By-laws
        Page 8
    Notes on the sharks of Florida
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
    Variations within successive categories of an extended series of extra-sensory discriminations
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
    Hitherto unrecorded vertebrate fossil localities in South-Central Florida
        Page 50
        Page 51
        Page 52
        Page 53
    Additions to the recorded pleistocene mammals from Ocala, Florida
        Page 54
        Page 55
    The role of hormones in the development of higher plants
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
    Torreya west of the Apalachicola River
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
    A physiographic study of the tree associations of the Apalachicola River
        Page 78
        Page 79
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
        Page 85
        Page 86
        Page 87
        Page 88
        Page 89
        Page 90
    Pretended accuracies in computations
        Page 91
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
    The necessity for artesian water conservation in the Florida Peninsula
        Page 97
        Page 98
        Page 99
        Page 100
        Page 100a
        Page 100b
        Page 100c
        Page 100d
    Notes on Florida water snakes
        Page 101
        Page 102
        Page 103
        Page 104
    Notes on the feeding and egg-laying habits of the pseudemys
        Page 105
        Page 106
        Page 107
        Page 108
        Page 108a
        Page 108b
        Page 108c
        Page 108d
        Page 108e
    A preliminary report on studies of moss habitats and distribution in North Central Florida
        Page 109
        Page 110
        Page 111
        Page 112
        Page 113
        Page 114
    Are women clairvoyant?
        Page 115
        Page 116
        Page 117
        Page 118
        Page 119
        Page 120
        Page 121
        Page 122
    Ovulation time in primates
        Page 123
        Page 124
        Page 125
        Page 126
        Page 127
    Holothurians from Biscayne Bay, Florida
        Page 128
        Page 129
        Page 130
        Page 131
        Page 132
        Page 133
        Page 134
        Page 135
        Page 136
        Page 137
        Page 138
        Page 139
        Page 140
        Page 141
        Page 142
        Page 143
        Page 144
        Page 145
        Page 146
        Page 147
        Page 148
        Page 149
    Academy personnel
        Page 150
        Page 151
        Page 152
        Page 153
        Page 154
        Page 155
        Page 156
Full Text


of the

Florida Academy





VOL. 3

Published by the Academy
Gainesville, Florida
June, 1939

* p r


Published annually by the Academy
Editor: L. Y. Dyrenforth
Managing Editor: J. H. Kusner
Editorial Committee: A. F. Carr
Ezda Deviney
C. I. Mosier
Maurice Mulvania
S. A. Stubbs
R. C. Williamson
A paper-bound copy of the Proceedings is sent to each member of
the Academy, without charge. A cloth-bound copy may be obtained,
instead, upon payment of $1.00.
The sale price of the Proceedings is:
Paper-bound-$1.00 per copy
Cloth-bound-$2.00 per copy
The Academy will be pleased to enter into exchange arrangements
with other scientific societies in any field and in any country.
Orders for copies of the Proceedings, subscriptions, exchange
publications, inquiries concerning exchange, and general correspond-
ence concerning Academy matters should be addressed to:
J. H. KUSNER, Secretary
Florida Academy of Sciences
University of Florida
Gainesville, Fla.




Secretary's Report.-J. H. KusNE ....-....................... .............- ...... 1
Report of the Acting Treasurer.-E. MORTON MILLER .............................. 3
Program of the Third Annual Meeting ....................... .......... .......... 4
Committees for the Third Annual Meeting ------...-- ....-------------.----------- 7
Changes in the By-Laws ...........-............. .........................- ..- 8
The Achievement Medal ........................... ... .............. 8
Research Grant ..................... ... .... ......... ...............----- -- 8


Notes on the Sharks of Florida.-STEWART SPRINGER ............................... 9
Variations Within Successive Categories of an Extended Series of Extra-
Sensory Discriminations.-ELIzABETH A. BECKNELL ...................... 42
Hitherto Unrecorded Vertebrate Fossil Localities in South-Central
Florida.- H. JAMES GUT .......................... .. ........ ...................... 50
Additions to the Recorded Pleistocene Mammals from Ocala, Florida.-
H JAMES GUT ............................ ......................... ........... .............. 54
The Role of Hormones in the Development of Higher Plants.-
W ILLIAM C. COOPER ...................................... .... ........................ 56
Torreya West of the Apalachicola River.-HERMAN KUR ........................ 66
A Physiographic Study of the Tree Associations of the Apalachicola
River.- HERMAN KURZ ................... .... ...... ........................... 78
Pretended Accuracies in Computations.-B. P. REINSCH .......................... 91
The Necessity for Artesian Water Conservation in the Florida Penin-
sula.- SIDNEY A. STUBBS ...................... ... .............. ............ 97
Notes on Florida Water Snakes.-E. Ross ALLEN ................ ............. ..... 101
Notes on the Feeding and Egg-Laying Habits of the Pseudemys.-E. Ross
A LLEN ...................... ----... ...---- ... ... ... .. ...................... 105
A Preliminary Report on Studies of Moss Habitats and Distribution in
North Central Florida.-RUTH SCHORNHERST ............................. ........ 109
Are Women Clairvoyant ?-JULIA H. HEINLEIN and CHRISTIAN P.
HEINLEIN ........ ....-------.---- ... ..---- .. ...................... 115
Ovulation Time in Primates.-JAMES H. ELDER ....................... .............. 125
Holothurians from Biscayne Bay, Florida.-ELISABETH DEICHMANN .... 128



Notes on the Histology of Siren.-G. G. SCOTT .............-----------. ................ 139
The Experimental Techniques of Scientific Psychology versus the Spec-
ulative Dogmas of Educational Psychosophy.-CHRISTIAN P. HEIN-
LEIN ..............--...............---.. ------------- --------- --------------- 139
Resonance in the Telephone and in the Cochlea.-MAx F. MEYER .......--. 140
The Basal Metabolism of College Women as Influenced by Race and
Degree of Activity.-LOLA SCHMIDT and JENNIE TILT ....................--- 141
Suggestions Concerning the Teaching of Biology.-G. G. SCOTT ....-------.. 142
Mental Hygiene in Secondary Education.-W. L. MAcGOWAN ............... 143
Psychometric Results and Notes on Behavior Before and After a Pre- ,
frontal Lobotomy on a Mental Patient.-PHILIP WORCHEL .....-......... 144
Conditions for Algebraic Solutions of Certain Ordinary Differential Equa-
tions of First Order and First Degree.-BARBARA DAVIS ........................145
The S-H Frequency of the Mercaptans.-DUDLEY WILLIAMS --.......------.... 145
Suggestions for an Improved Notation in Trigonometry.-H. H. GER-
MOND ............--..............----------...--------------..... 145
The Neutron.-D. C. SWANSON ............................. ---- ------ --.... --146
An Infra-Red Study of Several Liquid Crystals.-RICHARD TASCHEK and
DUDLEY WILLIAMS .....----...............-------------------- --------- -- 147
The Design of Numerical Problems for Instructional Efficiency.-H. H.
GERMOND ........----..........-- ------ ---- ----------------------- --------- .... 147
Semantic Analysis: A Basic Step in Scientific Method.-CHRISTIAN P.
HEINLEIN ...............---...--------------- ..--------------- --- --- -- 147
A New Concept of Florida Soils.-EDWARD T. KEENAN ..---.........- -- 148
Natural Phenomena.-MARY W. DIDDELL .........................-- .---- --------- 148

Officers of the Academy for 1938 .-...~.-.. _------...~.....----.--------- _. ------ 150
Officers of the Academy for 1939 ..-...........-.....--..---- -- ----------- 150
List of Members-1938 .... ----------........ .........------------.--.--- 151
Institutional Sustaining Members ...----....--------.....~........ 157


VOLUME 3 1938

During 1938 the membership of the Academy has continued to
grow. When the Academy was founded in February 1936, the ap-
plication for the Charter contained ninety-two signatures. By the
end of 1936 the membership had grown to 236, and at the Annual
Meeting of 1937 the membership totaled 262. Today the Academy
has 285 members in good standing. This is, of course, exclusive of
the memberships which have lapsed for non-payment of dues. Our
members are to be found in every part of the state, in every Florida
college and university, in 16 high schools and in many government
laboratories and other organizations of a scientific nature, both
within the state and elsewhere. Although this growth in member-
ship could hardly be called phenomenal, it is gratifying that we are
getting new members more rapidly than we are losing old ones.
Although we are hardly interested in the mere size of the member-
ship roll of the Academy, we undoubtedly do desire to have as-
sociated with us all those in the state who share our purposes and
who are worthy of membership in this science-wide and state-wide
scientific society which is, for Florida, the official counterpart of the
American Association for the Advancement of Science, with which
the Academy is affiliated.
There are undoubtedly many persons who would like to take part
in the activities of the Academy and whom we would desire to have
associated with us. The searching out of these people and drawing
them into membership in the Academy is a responsibility which
should be shared by all members. It is to be hoped that every mem-
ber who knows of others who are worthy of and would be interested
in membership in the Academy will nominate such persons for
At the 1937 Annual Meeting, the By-Laws were amended to pro-
vide for sustaining membership, both individual and institutional.


As a result of this action, the following six institutions have become
institutional sustaining members of the Academy:
University of Florida
Florida State College For Women
University of Miami
Rollins College
Florida Southern College
Stetson University
Incidentally, these six colleges and universities pay a total of $290
per year as their institutional membership dues.
It is to be hoped that such of our members as are connected with
institutions or organizations not yet contained in this list, will put
forth efforts to add their institutions to this distinguished roll. The
Secretary will be glad to consult with any members in the matter of
initiation of such moves.
The Academy has not been quite so fortunate in building up its
roll of individual sustaining members. The list of such members is
as yet extremely meager, and it is to be hoped that many more of
those members who are in a position to do so will undertake this
slightly increased responsibility of supporting the work of the
Academy. Transfer to Individual Sustaining Membership is open
to all regular members automatically upon payment of the small ad-
ditional sum of $3 which, incidentally, carries with it a cloth-bound
copy of the Proceedings instead of the usual paper-bound copy.
Many of us are hopeful that the list of individual sustaining mem-
bers will undergo considerable growth.
Acting on instructions from the Council, the Secretary's office has
made some progress in bring about exchange arrangements with
other scientific societies. Our Proceedings is now being ex-
changed with periodicals published by most of the academies and
many other scientific societies. It is expected soon to issue to all
members a list of the publications in the possession of the Academy
so that these may be available for their use, upon request.
The reception given to the first volume of our Proceedings has
been very gratifying. Unsolicited orders, requests for copies, or
offers of exchange have been received from places as remote as
Great Britain, Germany, and even China.
During the year, the Council of the Academy has had two meet-
ings apart from the Annual Meeting. One of these was held in
Gainesville and the other in DeLand. Of course, the bulk of the
Council business was conducted by correspondence, to which the


members of the Council of this year have paid serious and prompt
A considerable part of the work of the Secretary's office has been
carried on through the cooperation of the University of Florida
which has provided clerical and stenographic assistance and many
other aids. During the past year, the work of the Secretary's office
has been aided through the efforts of Dr. C. I. Mosier of the Univer-
sity of Florida who has occupied the post of assistant secretary
created at the 1937 Annual Meeting. Also, many other colleagues
have at various times during the year allowed themselves to be im-
pressed into the Academy's service.
The Secretary can truthfully report that the proportion of its
membership which has a strong interest in and loyalty to the
Academy is sufficiently large to augur well for the Academy's future
November 18, 1938 J. H. KUSNER, Secretary

(As of November 15, 1938)
Balance carried forward from November 20, 1937 ------------.------$734.39
Dues received: 1937 Memberships ..........-------------------.............. 116.00
1938 Memberships .---........ .--------...... --------........- 309.10
1939 Memberships ----......--------- ..... .............----- -- 14.00
1937 Associate Memberships -------................--- 6.00
1938 Associate Memberships ----------. ------....--- 5.00
1939 Associate Memberships ----..-...----..-------..- 1.00
1938 Institutional Sustaining Memberships 165.00
Receipts from the sale of Proceedings, Vol. 1 -------.--.------.. 29.00
A. A. A. S. Research Grant ----................--..--- -----....... ---..... 50.00

Publishing of Proceedings, Vol. 1 -------------.......--------- ---------------......$890.79
Maps-drawings for Proceedings ............... ---....... ......... 8.00
Administrative Expenses:
Secretary's Office, Postage and stationery .............-- ...... 65.47
Express and freight ---..--..............----- 41.78
Treasurer, Postage and envelopes ---------.......------..-----.........- 9.56
Business Manager, Express, telegrams, reprint covers -.. 14.85
Publishing of Programs, 1937 Meetings ---..--------....... -----.............. 25.50
Research Grant, 1938 ------ ------.. .......................... .... --............... 50.00
Miscellaneous: Book adjustments, reassignments of dues ...--- 4.00
Total Disbursements on order of
President and Secretary ---.....----.-----.---------.... $1,109.95
Balance, actual cash available -------.--.------. 319.54


1938 Institutional Sustaining Memberships -----....--.............------..... -$100.00
1937 Univ. of Florida, Purchase of Proceedings -------------------- ....100.00
1938 Memberships yet unpaid (approx.) ......-----------------------.......- 180.00
Reimbursements by authors for engravings in Proceedings, 1 .... 58.00

$ 438.00
E. MORTON MILLER, Acting Treasurer.


1. Two hour boat trip on Winter Park lakes.
2. Wekiwa Springs and Nature's Mystery.
3. Trip to Gentile Brothers' Packing House, Winter Park.
4. Inspection of Orlando Municipal Airport.
9:30 to 11:10 A. M.-GENERAL SESSION-Annie Russell Theater
President R. I. Allen presiding
1. Natural Phenomena-Mrs. W. D. Diddell, Jacksonville. 15 min.
2. The Austin Cary Memorial Demonstration Forest-H. S. Newins, Uni-
versity of Florida. 5 min.
3. The Vitamin C Content of Grapefruit-R. W. Harrison, Miami. 10 min.
4. A Report on the Water Snakes (Natrix) of Florida-E. Ross Allen,
Florida Reptile Institute, Silver Springs. 12 min.
5. A Preliminary Report on Studies of Moss Habitats and Distribution-
Ruth Schornherst, Florida State College for Women. 10 min.
6. A New Concept of Florida Soils-Edward T. Keenan, Keenan Soil Lab-
oratory, Frostproof. 15 min.
7. Notes on the Histology of Siren-George G. Scott, Winter Park. 5 min.

11:10 A. M. to 12:15 P. M.-MOTION PICTURES
(Marine Studios, St. Augustine, and Florida Reptile Institute, Silver Springs)
1:45 to 3:00 P. M.-GENERAL SESSION-Annie Russell Theater
President R. I. Allen presiding
1. Pretended Accuracies in Computations-B. P. Reinsch, Florida Southern
College. 25 min.
2. The Experimental Techniques of Scientific Psychology Versus the Specu-
lative Dogmas of Educational Psychosophy-C. P. Heinlein, Florida
State College for Women. 15 min.
3. Resonance in the Telephone and in the Cochlea-Max F. Meyer, University
of Miami. 20 min. (With demonstration.)


3':00 to 3:30 P. M.-INTERMISSION
Room 523, Knowles Hall
Chairman L. Y. Dyrenforth presiding

1. The Basal Metabolism of College Women as Influenced by Race and
Degree of Activity-Lola Schmidt and Jennie Tilt, Florida State Col-
lege for Women. 15 min. (Illustrated.)
2. A Comparison of the Plant Associations and Physiography of the Apa-
lachicola and Ocklockenee Rivers Flood Plains-Herman Kurz, Florida
State College for Women. 20 min. (Illustrated.)
3. Hitherto Unrecorded Vertebrate Fossil Localities in South-Central
Florida-H. James Gut, Sanford. 10 min.
4. Suggestions Concerning the Teaching of Biology-George G. Scott, Winter
Park. 25 min.
5. Holothurians from Biscayne Bay, Florida-Elizabeth Deichmann, Harvard
University. (By title.)

3:30 to 5:00 P. M.-PSYCHOLOGY SECTION-Room 509, Knowles Hall
Professor C. P. Heinlein presiding
1. Mental Hygiene in Secondary Education-W. Leroy MacGowan, Lee High
School, Jacksonville. 15 min.
2. Variations within Successive Categories of an Extended Series of Extra-
Sensory Discriminations-Elizabeth A. Becknell, Florida State College
for Women. 20 min.
3. Psychometric Results and Notes on Behavior Before and After a Pre-
frontal Lobotomy on a Mental Patient-Philip Worchel, Florida State
Hospital, Chattahoochee. 15 min.
4. Are Women Clairvoyant?-Julia H. Heinlein and C. P. Heinlein, Florida
State College for Women. 20 min.

6:00 to 8:00 P. M.-BANQUET-(Informal)
Assembly Room, Angebilt Hotel, Orlando

Toastmaster: Charlotte B. Buckland, Vice-President of the Academy.
Address of Welcome: Hamilton Holt, President, Rollins College.
Retiring Address': Robert I. Allen, President of the Academy.
Presentation of the Achievement Medal for 1937: W. S. Phillips, Chairman,
Achievement Medal Committee (1937).

"Science versus Unemployment," Science, Vol. 89, No. 2317 (May 26,
1939), pp. 474-9.


Room 523 Knowles Hall
Chairman L. Y. Dyrenforth presiding

1. The Role of Hormones and Vitamins in the Development of Higher
Plants-William C. Cooper, Bureau of Plant Industry, U. S. Depart-
ment of Agriculture, Orlando. 20 min.
2. Additions to the Recorded Pleistocene Mammals from Ocala, Florida-
H. James Gut, Sanford. 10 min.
3. Notes on the Sharks of Florida-Stewart Springer, Bass Biological Lab-
oratory, Englewood. 15 min.
4. Ovulation Time in Primates-J. H. Elder, Yale Laboratories of Primate
Biology, Orange Park. 15 min. (Illustrated.)
5. A Report on the Habits of Florida Terrapins-E. Ross Allen, Florida
Reptile Institute, Silver Springs. 12 min.

Room 509, Knowles Hall
Chairman B. P. Reinsch presiding

1. Conditions for Algebraic Solutions of Differential Equation Mdx+Ndy=O
where M and N are Polynomials-Barbara Davis, Apopka. 15 min.
2. The S-H Frequency of the Mercaptans-Dudley Williams, University of
Florida. 10 min.
3. Suggestions for an Improved Notation in Trigonometry-H. H. Germond,
University of Florida. 5 min.
4. The Neutron-D. C. Swanson, University of Florida. 15 min.
5. An Infra-Red Study of Several Liquid Crystals-Richard Taschek and
Dudley Williams, University of Florida. 10 min.
6. The Design of Numerical Problems for Instructional Efficiency-H. H.
Germond, University of Florida. 20 min.

10:00 to 10:30 A. M.-INTERMISSION
10:30 to 11:40 A. M.-GENERAL SESSION-Annie Russell Theater
President R. I. Allen presiding

1. Semantic Analysis: A Basic Step in Scientific Method-C. P. Heinlein,
Florida State College for Women. 20 min.
2. The Necessity for Artesian Water Conservation in Florida-Sidney A.
Stubbs, University of Florida. 10 min.

11:45 A. M. to 12:15 P. M.-BUSINESS SESSION-Annie Russell Theater

12:15 P. M.-COUNCIL MEETING (Both new and retiring members)



Guy Waddington, Rollins College, Chairman
W. S. Anderson, Rollins College
R. T. Robinson, Orlando
G. G. Scott, Winter Park
Bernice C. Shor, Rollins College
E. R. Weinberg, Rollins College
W. Others, Orlando

Herman Kurz, Florida State College For Women, Chairman
R. S. Bly, Florida Southern College
C. B. Buckland, Landon High School, Jacksonville
J. H. Clouse, University of Miami
S. A. Stubbs, University of Florida
C. B. Vance, Stetson University
Sarah P. White, Florida State College for Women

R. C. Williamson, University of Florida, Chairman
E. Deviney, Florida State College for Women
L. Y. Dyrenforth, St. Luke's Hospital, Jacksonville
E. D. Hinckley, University of Florida
M. Mulvania, Florida Southern College

B. P. Reinsch, Florida Southern College, Chairman
W. M. Barrows, Florida State College for Women
R. T. Robinson, Orlando

'E. F. Weinberg, Rollins College, Chairman
C. I. Mosier, University of Florida

B. Faust, Edison Senior High School, Miami, Chairman
B. McAllister, Miami



is awarded annually for a noteworthy paper presented at the annual
For the 1938 Annual Meeting, the medal was awarded to Stewart
Springer, Bass Biological Laboratory, Englewood, for his paper
"Notes on the Sharks of Florida," published in this volume, pp. 9-41.
The committee which selected the paper to receive the award is
listed on page 7 of this volume.

SCIENCE allotted $50 for use as a grant in aid of research, to be
awarded to a member of the FLORIDA ACADEMY OF SCIENCES.
The Council of the Academy awarded the grant to Sidney A.
Stubbs, Florida State Museum, University of Florida, for field work
in a study of the fauna, geographical distribution and structure of
a recently discovered' artesian aquifer older than the Ocala lime-
stone, and the relationship of this zone to other Eocene horizons of
the Atlantic Coastal Plain.

At the 1938 Annual Meeting certain divisions of the By-Laws were amended.
The changes in these divisions are given below. All other portions of the
By-Laws remain as given in Volume 2 of the Proceedings, pp. 92-94.
3. The Secretary shall keep the records of the Academy and of the
Council and shall act as Managing Editor of the PROCEEDINGS. He
shall have charge of the sale and exchange of the PROCEEDINGS. Sub-
ject to the approval of the Council he may appoint an Assistant Sec-
retary to assist him in performing his duties.
2. The PROCEEDINGS shall be under the immediate control of the Council,
through an Editor, a Managing Editor, an Editorial Committee of
which the Editor shall be Chairman ex-officio, and a Business Man-
ager. The Editor, Editorial Committee, and Business Manager shall
be appointed by the Council each year for the volume of the Pro-
ceedings of that year.

SSee S. A. Stubbs, "A Study of the Artesian Water Supply of Seminole
County, Florida," these Proceedings, Vol. 2 (1937), pp. 24-36.


Bass Biological Laboratory, Englewood

The sharks, rays, and chimaeras make up the class, Elasmo-
branchii. The fishes make up a separate class Pisces, and the dif-
ferences between members of the two classes are considerable.
While it is unnecessary to go into these differences here, I do wish
to emphasize the fact that there is a large gap between the two
groups, and to point out the necessity for the appreciation of these
differences in taxonomic studies. Our knowledge of the Elasmo-
branchii is not without its bright spots, but it is weak as compared to
our knowledge of other vertebrate classes. In working out systems
of classification, the taxonomist is fundamentally concerned with the
morphological facts, but if there is a background of knowledge about
the organism that is reasonably comprehensive, he can interpret the
data derived from a study of the specimen, and erect a system with
much greater meaning. The study of sharks is handicapped by both
the lack of great collections of specimens and a background of
knowledge about the life histories of those specimens before they
entered the alcohol bin or bottle.
The fragmentary information I have gathered can not have much
value unless it is followed up. My facts are too few for the inter-
pretations or assumptions I have made, and the interpretations do
not satisfactorily cover the facts. But a start must be made some-
where, and I do have a specific purpose in presenting this paper.
Sharks are frequently bulky and hard to handle. They are expen-
sive to collect and time consuming to examine. Museum facilities
do not permit the storage of series of large specimens. Therefore,
it is desirable to take the maximum advantage of any material that
becomes available. A large quantity of material is collected by the
shark fishery in Florida. Each shark is subject to some handling
and at least one measurement, and at some stations, the catch is
reported on daily. There has not been any general agreement on
the names of the sharks included in these reports, and it is my hope
to set some standard in the use of common names. I have given
preference to common names in general use by the fishery without
particular regard to the common names applied by ichthyologists.

for 1938.


The scientific nomenclature applied to sharks is badly muddled,
species have been poorly described, and where large species are con-
cerned there are rarely any types. The obvious procedure of com-
paring sharks from different parts of the world is impractical.
Consequently, I have emphasized some characters and described
them in more detail, so that they may be compared with those
characters for sharks in other parts of the world.
Most of the material used in the preparation of this paper has
been collected at Bass Biological Laboratory by members of the
staff, and at the stations of Shark Fisheries, Inc. I am particularly
indebted to Mr. John F. Bass, Jr. for facilities for carrying out
investigations, for financial assistance in gathering material, and
for many helpful suggestions. I wish to thank the personnel of
Shark Fisheries, Inc. and Mr. Ferd Dalton of Bass Biological Lab-
oratory for their very helpful co-operation.

The initial impression to be gained from an examination of shark
specimens with an attempt to identify them, is that great variation
in form exists; and variation in form there is, but a very large part
of it is change in form due to growth, and a comparison of specimens
of exactly equal size shows remarkable similarity of form. I origi-
nally thought that the measurements I had taken of Isogomphodon
limbatus indicated variation in form, but an analysis of them led me
to the discovery that two species were involved. Poey recognized
and described 1. maculipinnis years ago, but ichthyologists have not
recognized his species, possibly because they have had to work with
a small number of young specimens.
While the material has not been sufficient to treat problems statis-
tically, it has been possible to draw some inferences from the series
of measurements I have for a few species. Alteration of the body
form, in the species of Carcharinus, is apparently much greater when
maturity is reached. The snout becomes shorter and the fins be-
come proportionately longer. The relative positions of the pectoral
and first dorsal remain about the same, but the proportions of the
head and tail regions are greatly changed. The size of the eye
decreases proportionately with age in Carcharinus milberti and prob-
ably in Carcharinus obscurus, but in Carcharinus platyodon the rela-
tion of the eye size to total length remains about the same.
Maturity is reached at a fairly definite size in each of the species
I have studied. In so far as my material goes, adult sharks of any
given species are all about the same size. I have no doubt but that


the size range of adults is a useful character for the separation of
species. Unfortunately, I cannot get any conclusive data for the
larger species. Most of the adult tiger sharks taken by the Florida
shark stations range from ten and a half to thirteen feet in total
length. It is possible that some individuals as long as fifteen feet
have been taken, but I have not found any objective evidence of
these very large ones. I have seen probably twenty thousand tiger
shark teeth, taken in Florida and West Indian waters in the past two
years, and in the lot there have been none that exceeded the teeth of
a thirteen foot specimen in size. This might be conclusive evidence
that extremely large individuals exist only as abnormalities except
for the fact that the shark fishery uses a more or less standardized
equipment which will catch some thirteen foot sharks and not much
more. The two great white sharks recorded here were taken on
unusually strong equipment, a combination of steel cable and rope,
probably capable of withstanding a much greater strain than the
ordinary chain lines.
Fertilization is internal in all the sharks. The young are either
born alive, or the fertilized eggs are deposited in heavy impervious
egg cases. Within the class Elasmobranchii there is an amazing
variety in specialization of structures to effect internal fertilization
and to provide nourishment for the developing embryos. The num-
ber of young born at one time varies greatly with different species.
Some of the smaller sharks have a fairly definite period for re-
productive activity each year and mature females collected in the
proper month will all contain embryos. For the tiger shark and
the three large Carcharinus, there does not appear to be any certain
period at which embryos can be collected. It is possible that they
are produced at irregular intervals. I have not collected any reliable
data on the sex ratio of the large sharks. I have had difficulty in
getting measurements of enough mature males of the larger species,
although I have always selected males for examination when there
was any choice.
Probably most of the sharks are of little importance as enemies of
food fishes. A possible exception is the sand-tiger. The common
tiger shark may devour enough of the spiny lobsters to be of
economic importance. The mako shark and the great hammerhead
get injured or spent game fish. The mako may be fast enough to
catch some of the larger uninjured fish, but if the hammerhead gets
any it must be on the basis of its superior maneuverability.


Sharks move about, sometimes for considerable distances, but no
investigations of the extent and regularity of their migrations have
been made. At Englewood, there are several species which we have
taken only in winter and several species which have been collected
only in summer. At Salerno, this division is much less clear cut.

(indicated by X)

Shark : < ;
Nurse .------------------------ x XX XX X X
Gulf smooth hound ---.. x x x x
Tiger ----..- --------- x x x Xx x X
Bull ------------------- x x X X x x
Black nosed .-............. x x X x x x x x XX
Sand-bar --------------. X X X X X
Dusky ....------------------- X I X
Spot-fin .---..---.--- --- i x x x x X X X
Black-tip ---------------- X X X
Lemon ..---------------------- x x x X XI X x X
Common hammerhead ...-. X X X X x X
Great hammerhead ...... X x X I X XX X
Sand tiger .-...-....---.---------- X Xi

The fluctuations in the percentage of a given species in the total
weekly catch suggest an irregular wandering on the part of large
schools or looser aggregates of individuals. Of the seventeen
species taken at Englewood, the free swimming young of only eight
have been collected, and I doubt whether the shallow water off
Englewood is within the range in which the other nine liberate the
Sharks are not used as food in this country, and at present the
flesh of sharks taken in Florida has no market value. The carcasses
have been cut into strips, dried, and ground for fertilizer but this
has been carried out on an experimental basis and most of the
carcasses of sharks caught in Florida are discarded. The dried fins
find a ready market at a high price per pound for fishery products.
The hides are the most valuable single product of the shark fishery,
and as the supply is not great, the chances of overproduction are
slight. The liver oil is in demand and most of the better quality oil


taken from the Florida shark fishery is processed by a Florida com-
pany. Most of the revenue derived from the Florida fishery comes
from the hides, fins, and liver oil. The teeth are sometimes sold,
and it is probable that the carcasses will eventually be utilized. In-
vestigations are being made as to the possibilities for the production
of a very active pepsin from the stomachs of freshly killed sharks.
The industry in Florida is not large, but it is not beset by the
dangers of overproduction, and should flourish as long as the supply
of sharks remains at the present level. The industry should know
how far it can expand without the dangers of overfishing. Bio-
logists can only guess without knowing more about the life histories
of the sharks. Questions of the rate growth of the various species,
the number of young produced, the frequency of the production of
young, the nature and abundance of the food supply, and the kinds
of natural enemies should be answered. Probably the best and
quickest way to get at these problems is by tagging the young sharks.

1. Gingylostoma cirratum (Gmelin). THE NURSE SHARK.
The nurse sharks are confined to the tropical and semi-tropical
waters of the western hemisphere. It appears to be problematical
whether more than one species exists, but only one is to be found
regularly on the coasts of Florida, where it is common south of the
latitude of Tampa, and is present in summer at least as far north as
the state line.

FIG. 1.-THE NURSE SHARK, Gingylostoma cirratuin
Mature specimens are from seven and a half to eleven feet long.
They are big headed, somewhat flattened sharks with relatively
small, but enormously powerful jaws. The jaws are armed with
many small teeth, several rows of which are functional. The mouth
is close to the tip of the snout, but is definitely inferior and is pre-
ceded by a pair of cylindical nasal cirri. The color is a rich uniform
brown, lighter on the belly. Young individuals are spotted with
darker color and the spots occasionally persist on old ones.


The dermal denticles are heavy, close-set, and smooth, forming a
very strong-armor. No doubt this armor is important to a heavy
bottom-feeding shark inhabiting coral reef areas, and it is probable
that it makes the nurse shark nearly immune to the attacks of other
The species is said to come into shallow water for mating. Com-
plete shells are produced for the eggs but these are thought to be
retained until after hatching.
Nurse sharks take hooks baited with fish, and the stomach of one
large specimen from Englewood contained a quantity of crab shell.
The hides bring a slightly higher price than those of other local
species, but the fins are not in demand and the liver oil yield is
relatively low.

2. Mustelus canis (Mitchill). THE COMMON SMOOTH HOUND.
No Florida specimens of this species have passed through my
hands, but I have seen specimens from Cuban waters and from the

A cO--
Typical tooth

coast of Virginia. Smooth hounds are abundant in winter off Nor-
folk in relatively deep water, usually from November through Febru-
ary; but during this period they travel in large compact schools,
which, I am told by fishermen, are not easy to locate in the coldest
part of the winter. No doubt they come further south, as the
existence of Cuban specimens would indicate, and deep-water fish-
ing with otter trawls in winter on the east coast of Florida might be
expected to produce specimens.
At Norfolk I examined a lot of some five thousand pounds of
smooth hounds, all taken in one drag by an otter trawl in about fifty
fathoms. These were taken in early February, and ranged in length
from 510 mm. to 1100 mm. Sexually mature specimens in this lot
were all more than 750 mm. in total length. Most of the large


females contained embryos at about the same stage of development;
the embryos from 200 mm. to 260 mm. long. The average number
of young carried by females, in a lot of ten examined after preserva-
tion, was eleven. The embryos are nourished by means of a pseudo-
placenta, at least for the later period of development.
During the warmer months the smooth hounds move northward
and into shallow water and are rare south of New Jersey.

3. Mustelus norrisi Springer. THE GULF SMvOOTH HOUND.
This small, slender, smooth dogshark is known only from a
series of adult males taken at Englewood and a single female with
embryos taken near Key West in 1906. All were collected in the
winter months. I have been told by Englewood fishermen, who
know the species, that during February, 1938 large numbers were
taken in mackerel nets off Naples, Florida. As the fish fauna of
the Gulf of Mexico in waters of moderate depth is little known, it
is not surprising that the species has been infrequently taken. It is
possible that the Gulf smooth hound is common in waters of fifty
fathoms and that it comes into shallow water only when the temper-
ature of the water is down.

D I f f i l l ,

FIG. 3.-THE GULF SMOOTH HOUND, Mustelus norrisi
Mustelus norrisi is very close to Mustelus lunulatus Jordan and
Gilbert, which is found in the Gulf of California. It differs chiefly
in having the origin of the first dorsal back of the inner angle of the
pectoral instead of in advance of it. Mustelus norrisi may be dis-
tinguished from Mustelus canis by a comparison of the teeth and
jaws of adult specimens. In the Gulf smooth hound the jaw is nar-
row, strongly arched, and the line of occlusion of the jaws forms an
angle of 90 degrees or less at the middle of the mouth. The teeth
are high' crowned. In the common smooth hound the teeth are low
crowned and the angle formed by the jaws is more than 90 degrees.
With the characters given in the key, identification of the two forms
should be comparatively easy.


4. Galeorerdo arcticus (Faber). THE TIGER SHARK.
The common name most frequently applied to this shark by Flor-
ida fishermen is leopard shark, the name tiger shark being given to
the big sand shark, Odontaspis. Galeocerdo arcticus has a wide
distribution in warm seas and the term tiger shark is in general use
for it and preferable. Tiger sharks are present on the coasts of
peninsular Florida throughout the year, and are probably present in
the north Gulf and in Atlantic waters north of Florida during the
warmer months.

1T Typical tooth of either jaw.
FIG. 4.-THE TIGER SHARK, Galeocerdo arcticus
Young specimens are spotted or banded with darker color, but
these markings are obscure or absent on large individuals. The
shape of the teeth especially, together with the presence of small
spiracles and heavy lateral keels will serve to distinguish this species
from all other sharks.
Tiger sharks are probably the largest and most powerful of the
common species to be found on the Florida coast. The large
coarsely serrate teeth are extremely efficient cutting instruments.
Only one series is functional and the bites taken by the shark are
generally smooth and clean. Bites on large objects are made by a
rolling motion with both jaws cutting much in the manner of a saw,
and if the object bitten is large enough to offer resistance, the tiger
shark is quite capable of cutting through bone and shell. These
sharks are very destructive to gill nets, biting out great holes to take
a single fish, and, swimming back and forth through the nets as they
feed on the gilled fish, they pile up many hours of net mending for
the unlucky fisherman.
Stomachs of tiger sharks taken at Englewood most frequently
contained horseshoe crabs, small sharks or pieces of large ones,
small sea turtles or pieces of large ones, sting rays, tin cans, cormo-
rants, spiny lobsters, and migratory birds such as warblers. Horse-
shoe crabs formed the largest part of the stomach contents and very


few bony fish remains were found. Although spiny lobsters are not
often taken at Englewood, the remains were regularly taken from
tiger shark stomachs in the spring of 1938. Probably this shark
may be classed as an important enemy of the larger crustaceans and
the horseshoe crab as well as a scavenger.
From thirty to fifty young may be born at a time. There is evi-
dently no special period of the year at which the young are liberated.
Early and late embryos have been taken from Englewood specimens
in April and very early embryos have been found in June.
The tiger shark is one of the most valuable species to the shark
fishery. The hides, liver oil, and fins find a ready market. The
liver of a single specimen may yield as much as fifteen gallons of
high quality oil. The amount of oil in the liver of female sharks
seems to be correlated with the development of the young, a high oil
content being present when there are ripe ova in the oviducts and
a low oil content being present when there are nearly full term

5. Prionace glauca (Linnaeus). THE GREAT BLUE SHARK.
This is a very large shark, more truly pelagic than any of the
other species of the family Carcharinidae. It is found in most seas,

7 / \l, ^^ Tooth of upper ja'0, aa'rat.
FIG. 5.-THE GREAT BLUE SHARK, Prionace glauca,
but is apparently rare in Florida waters. I have seen one photo-
graph of a catch of sharks, taken by anglers off Miami, which may
include a specimen of this species, and I have one lot of teeth from
a small specimen from the Salerno shark station carcass dump. Mr.
Mooney, manager of the station, assures me that the teeth must have
come from the stomach of some other species, and that no great blue
sharks have come in.
Blue sharks are said to reach a length of twenty or twenty-five
feet. There is no equipment at any of the shark stations that would


hold a specimen of such size, and large, wandering individuals may
be much commoner than captures indicate.
The curved serrate teeth of the upper jaw, differing in shape from
those of the lower jaw, afford the best means of identifying the

6. Scoliodon terra-novae (Richardson). THE SHARP-NOSED
Several species of the small sharks of the genus Scoliodon have
been described from the West Indian region. While a large number
of specimens have been taken at Englewood, and these specimens do


Tooth from upper jw
Tooth from lower jaw.
FIG. 6.-THE SHARP-NOSED SHARK, Scoliodon terra-novae

show more range of variation than I have seen in other ground
sharks, I have not compared them with series from other localities
and have not compared series of summer and winter collection.
It is possible that two species may be involved, and that both are
regularly present in south Florida waters. The sharp-nosed sharks
range from Cape Cod to Brazil and are common on the Florida
coasts. They are small sharks, about three feet long when mature,
and consequently, of little importance to the commercial fishery.
Scoliodon terra-novae differs from species of Carcharinus,
Hypoprion, Isogomphodon, and Aprionodon in having relatively long
labial grooves running forward from the corners of the mouth; and
in having teeth similar in shape in the upper and lower jaws, oblique,
deeply notched on the outer margins, with the points of all but the
central teeth directed toward the angles of the jaws.
Large schools of sharp-nosed sharks frequent the passes into
Mississippi sound during the summer months but are absent during
the winter. Collections were made there during the months of June
through September.in 1931, 1932, and 1933. In the total catch of


many hundreds of individuals, only a few (less than ten) half
grown specimens appeared. Early in the summer, only adult males
were collected on hook and line in any quantity. Females were
present in the area, but not in schools with the males, and only a
small:number were taken on hook and line. In August the newborn
young were frequently taken on hook and line in the sound, and in
September the schools of adult sharks included a large proportion
of females.
At Englewood, specimens have been taken in all months and the
number of half-grown specimens is proportionately great in both
spring and fall catches.In mid-summer the species is not common.
Females with early embryos have not been taken.

7. Carcharinus platyodon (Poey). THE BULL SHARK.
Bullhead shark has been used in Florida as a name for this species,
but I propose the name bull shark because the former name has wide
acceptance for species of sharks of the family Heterodontidae. In
Florida, the species is also called mackerel shark or mullet shark
because it is supposed to follow schools of these fishes. Actually,
the bull shark is probably too slow to catch either, and mackerel
shark is a better name for the swift, fish-eating sharks such as the
mako, in which the lower caudal lobe is well developed, forming a
tail fin similar in shape to that of a mackerel.

A,o interdorsal skin ridge here.

pper Saw too Tootb from lower jaw

FIG. 7.-THE BULL SHARK, Carcharinus platyodon

Most authors have included both this species and another closely
related one, Carcharinus commersonii in accounts of the West
-Indian fauna. I have seen but one form from Florida, and, on
rather slender evidence, have chosen to recognize it as distinct from
the Mediterranean Carcharinus commersonii. On theoretical
grounds I would be inclined to doubt the existence of. West Indian


specimens of that species. Poey's description of Carcharinus
platyodon is a good one, and covers characters not subject to varia-
tion or growth changes.
The genus Carcharinus is a large one, well represented in the
shore waters of most temperate and tropical seas. It includes an
assemblage of sharks of medium and large size, which are very
similar in appearance, although differences in the shape of the teeth,
in the structure of the dermal denticles, and in the relative positions
of the fins are sometimes considerable. In so far as the material I
have examined is concerned, the Florida species do not show any
marked variation. The characters which have been used for the
demarcation of species have frequently been those relating to length
of fins, length of tail, and length of snout. As I have already
pointed out, these characters are modified during growth, and while
they may be useful when large series are available for the identifi-
cation of species, they are misleading in giving the impression of
variation in form within a species. The characters I have given in
the accompanying key are apparently stable, nevertheless, identifi-
cation of specimens within the genus Carcharinus is sometimes dif-
Carcharinus platyodon is found on the Gulf and Atlantic coasts
of Florida, and ranges through the West Indies from Texas to the
Carolinas. At Englewood, we have not taken specimens in Decem-
ber, January, or February, the species being then replaced by
Carcharinus milberti and Carcarinus obscurus.
The bull shark is a large, heavy bodied species, becoming mature
at slightly more than seven feet in length and reaching a little more
than nine feet. The snout is short and broadly rounded, its length
being much less than the width of the mouth. The color is usually
light gray above and white below, without any conspicuous fin mark-
ings. A few of the specimens I have seen have been quite dark,
and it is possible that the form occurs in two color phases, or that
the color may be modified by environmental factors. There is no
trace of an interdorsal ridge. The origin of the first dorsal is in
advance of the inner angle of the pectoral fin. Typical teeth of the
upper jaw are nearly erect and triangular, only slightly angled to-
ward the sides of the mouth, serrate and quite sharp. Typical
teeth of the lower jaw are erect and narrow, with fine serration.
The lower jaw teeth may be described as two rooted; that is, the
lower surface of the basal portion is quite concave, and the enamel
line of the outer surface curves upward at the center of the tooth.
The lower jaw teeth are proportionately heavier than those of the


dusky shark and the sand-bar shark, with the point more abruptly
tapering. The tooth count on seventeen mature specimens taken at
12 1 12 13 1 13.
Englewood was 12 1 12 to 3 1 12 In this formula the fig-
12 1 12j 13 1 12
ures above the line refer to the number of rows of teeth in the upper
jaw, twelve or thirteen rows on either side of the jaw and one
central tooth at the symphysis.

8. Carcharinus acronotus (Poey). THE BLACK-NOSED SHARK.
Specimens of this small species have been taken on the Atlantic
coast at least as far north as the Carolinas, and the species is abun-
dant on the west coast of Florida. I have seen at least one specimen
from Biloxi, Mississippi, and the species was described by Poey
from Cuban specimens. It does not reach a large enough size to be
of importance to the commercial fishery.

,N o nterdersal skin ridge here.

Typical upper tooth, serrate

Typical lower tooth, finely serrate.;
FIG. 8.-THE BLACK-NOSED SHARK, Carcharinus acronotus
The black-nosed sharks taken at Englewood have appeared in two
color phases. Most of them were cream colored above and white
below, without definite fin markings, but with the snout tipped with
darker color. Some were uniform brown except for the darker
snout tip. While the black or darker colored nose is a good field
recognition mark for fresh specimens, I am not sure that the color
would be especially noticeable on preserved ones. The nose spot is
well marked on young, but becomes obscure and diffuse on old
These sharks are mature at about three feet four inches, and may
reach a length of four feet six inches. The origin of the first dorsal
is over or slightly behind the inner angle of the pectoral. There is
no interdorsal skin ridge. The teeth of the upper jaw are strongly
notched on the outer margin, oblique, and roughly triangular in out-
line. Serrations on the teeth of the upper jaw are just visible to


the naked eye.The teeth of the lower jaw are narrow and erect on
broad bases, and.the serrations can be seen only with the aid of a
microscope. Tooth counts of ten mature specimens from Engle-
12 1 12 13 2 13.
wood run from 1 to 1
11 1 11 11 1 11
At Englewood nearly full term embryos have been collected from
January to April, three to six being taken from a single female.
Full grown black-nosed sharks have frequently been taken from
the stomachs of tiger sharks and bull sharks.

9. Carcharinus milberti (Valenciennes,). THE SAND-BAR SHARK.
It is not improbable that there are two species in the material I
have seen and referred to Carcharinus milberti. Both Mr. Charles
Mooney and Mr. Guy Hunt of Shark Fisheries, Inc., tell me that
they have noticed two kinds of sand-bar sharks in their catches on
the east coast of Florida, one is the smaller and commoner, more off-
shore species which is certainly C. milberti, Mr. Mooney tells me
that the other form is larger and is taken on the inshore lines. In
my measurements of Englewood sharks, I have noted one specimen
which I originally thought to be Carcharinus falciformis (Bibron).
Subsequently, I removed this specimen from consideration because
of an obvious error in one of the pectoral fin measurements. The
specimen was much too large, nine feet nine inches, for a sand-bar
shark, the origin of the first dorsal was almost over the inner angle of
the pectoral instead of well in advance, and the tooth count was
15 2 15,
15 2 1, near the extreme for the sand-bar shark. Unfortunately,
14 1 14
I did not make an examination of the dermal denticles and did not
save a skin sample.
The exact range of the sand-bar shark is not known. Certainly,
it is found on the coast of the northern states in summer, and, al-
though I can find no definite record of the species for Florida, it is
the most abundant of the commercially valuable sharks taken at
Salerno on the east coast of Florida. We have it with Carcharinus
obscurus at Englewood, replacing Carcharinus platyodon in the
catch of the shark station during late December, January, February,
and early March in the winter of 1937-1938.
In the northern part of its range this form has been called the
brown shark but all the specimens I have seen from Florida have
been slate-gray. It is possible that, along with Carcharinus acrono-


tus, this shark may have color phases or have the color modified by
the environment.
The sand-bar shark may be distinguished from other Florida
species of the family most certainly, by an examination of the dermal
denticles with a microscope. In the sand-bar shark, typical denticles
on the skin of the side a few inches below the mid-dorsal line are
widely spaced, not touching one another, and with the skin showing
through. The denticles are three to five ridged in adults, wider than
long, and with the points made by the ends of the ridges at the
posterior end of the denticles scarcely projecting.
No very satisfactory characters have been given in the past for
separating C. milberti from all the rest of the genus, and while the
material I have seen is not sufficient to do this, some comparisons
may be of interest to students. Both Carcharinus japonicus

Vertical through Inner angle of pectoral
Vertical through the
origian of first dorsal An interdorsal skin ridge here

T ooth of lower jaw,
(j Vt A very finely aerrate
-Teeth of upper jaw, serrate

FIG. 9.-THE SAND-BAR SHARK, Carcharinus milberti

(Schlegel) and Carcharinus dussumieri (Muller and Henle) have
widely spaced denticles, broader than long, and both have an inter-
dorsal skin ridge, although in the specimens I have seen, the spacing
of the denticles is not so wide as in C. milberti. The teeth of C.
japonicus are smaller in specimens of comparable size, and more
oblique in the upper jaw, resembling those figured in Muller and
Henle, "Der Plagiostomen," 1841, for Carcharias menisorrah Muller
and Henle. The very oblique teeth of the upper jaw and the long
slender nasal flap serve to distinguish C. dussumieri from C. milberti.
In all three species the relative positions of the second dorsal and
anal are somewhat variable and entirely worthless for consideration
as distinguishing features.
Unless the larger inshore form already mentioned turns out to be
the same as the common offshore form it should be possible to set a
fairly definite limit to the size range of the species. For the present,


I shall eliminate the larger form from the discussion, and assume
that it is an unidentified species or the hybrid of C. milberti and the
closely allied C. obscurus.
The sand-bar shark becomes mature at about six feet eight inches,
and very large specimens may be as much as seven feet ten inches
in total length. It is a heavy bodied shark, but not quite so big-
headed as the bull shark. The width of the mouth of adults is about
one and one-half times the length of the snout, measured from the
front of the mouth. There is an interdorsal skin ridge. The origin
of the first dorsal is well in advance of the inner angle of the
pectoral. In adults the pectoral fins are long, and when folded back
along the sides, reach well past the end of the base of the first dorsal.
The distal margin of the pectorals of adults is somewhat concave.
In the embryos, however, the pectorals reach past the base of the
first dorsal, but the distal margin is nearly straight. The origin of
the second dorsal is either over, slightly in advance, or slightly in
back of the origin of the anal.
The teeth are comparatively larger than those of the dusky shark
and comparatively smaller than those of the bull shark. The upper
teeth are similar in shape to those of the bull shark, usually as high
or higher than broad and centrally nearly erect, while the lower teeth
are similar to those of the dusky shark, but are smaller, narrower,
and without the cupped base and central groove of the lower teeth
of the bull shark. The tooth count in the specimens examined has
14 1 14 15 2 15.
run from to
13 1 13 14 2 14
Three, of the sixteen mature females taken at Englewood, carried
embryos, all from 380 mm. to 440 mm. in length, and in litters of
eight, eleven, and twelve. No young sand-bar sharks have been
collected at Englewood.

10. Carcharinus obscurus (Lesueur). THE DUSKY SHARK.
The dusky shark is known from the Atlantic coast of the United
States. I do not find definite records of the species from Florida,
but it is to be found on the lower west coast, at least in winter, and
on the east coast is common throughout the year.
It is a larger species than either the sand-bar shark or the bull
shark, and has a proportionately longer snout and smaller teeth.
The presence of an interdorsal skin ridge in specimens of all ages
will distinguish the dusky shark from the bull shark. It differs
from the sand-bar shark in having the origin of the first dorsal in
back of the inner angle of the pectoral rather than in advance, and


in having the distal margins of the pectoral fins of the embryos
The upper surface is dirty gray and the lower surface white with
the lower surface of the pectoral fins tipped with black. Some
specimens are very light in color and the species is occasionally refer-
red to as the white shark. The second dorsal is smaller than the
anal and about opposite it. The teeth of the specimens examined
usually give a slightly higher count than the teeth of C. milberti, but

Vertical through origin of first dorsal
Vertical through inner 1
angle of the pectoral
An interdorsal ridge here.

Teeth of lower jaw,
very finely serrate.
Tooth of upper Jaw, aerrate
FIG. 10.-THE DUSKY SHARK, Carcharinus obscurus

counts from the two species are overlapping. The tooth counts of
14 2 14 15 3 15.
the dusky shark have run from 4 4 to he
14 1 14 14 3 14
upper teeth are broadly triangular, with the margin toward the
angles of the jaws concave and the opposite margin convex. Typi-
cal teeth are broader at the base than high, the height measured
along the tooth axis. The teeth of the lower jaw are narrow, erect,
and have broad bases without the central groove and cupped base
which is characteristic of the teeth of C. platyodon. The upper
teeth are coarsely serrate, and the lower teeth are very finely serrate
on the cusps only.
Nine adult females, ranging in length from ten feet four inches
to eleven feet eight inches, were examined. Two of them carried
embryos. One litter of ten, taken at Englewood on January tenth,
included embryos from 575 mm. to 585 mm. long. Embryos of the
second lot, taken January twenty-first, were from 950 mm. to 965
mm. long.
Dusky sharks have been collected at Englewood only in December,
January, and February, and no young, half-grown individuals, or
adult males have appeared in the collections made there.


11. Isogomphodon limbatus (Miiller and Henle). THE SPOT-FIN
The recent tendency of taxonomists has been to regard this species
as one of almost cosmopolitan distribution, with wide variation in
form, as the size and shape of the teeth, and in the number of rows
of teeth. An examination of the large numbers of specimens col-
lected by the Englewood shark station has shown, that instead of
one variable species, we have two species without marked variation
for the characters mentioned. It seems unlikely to me that
Isogomphodon limbatus ranges much beyond the West Indian region

Inner angle of pectoral, posterior
Origin of first dorsal, anterior Bo interdorsal skin ridge here.

Tooth from upper jaw, serrate.
Tooth from lower jaw, finely serrate
FIG. 11.-THE SIor-FIN SHARK, Isogomphodon limbatus

except possibly up the Atlantic coast of North America as a migrant.
As this and the following species have generally been considered
synonymous, and the diagnostic features are not given in faunal
lists and other publications, it is difficult to assign a range to either.
Isogomphodon limbatus has been taken at Englewood in all months
except December, January, and February, at which time, it is re-
placed by Isogomphodon maculipinnis.
1. limbatus may be mature at six feet in length and probably does
not ordinarily reach a length of more than seven and a half feet. It
is probably swifter than species of Carcharinus, and it does manage
to catch some bony fishes. Although it is at least as abundant, it
does not appear so often in the stomachs of the larger sharks as
Carcharinus acronotus. Both the species of Isogomphodon give a
fast and furious fight when taken on hook and line, often leaping
clear of the water. If is possible to wear them out more easily than
the kinds of sharks that come up and fight the boat.
Both the species of Isogomphodon are gray above and white below
with the tips of the pectorals black. The other fins are often black
tipped or edged with darker. The line formed on the sides by the
meeting of the darker dorsal color with the lighter ventral color is



usually clear cut and the lighter stripe, shown in the figure of I.
limbatus, is definite, although it appears in many species of Car-
carinus and related genera, it consequently has little value as a diag-
nostic feature. There is no interdorsal ridge. The teeth of the
upper jaw of this shark are very narrowly triangular on broad bases,
with straight-sided somewhat oblique cusps, and serrations which
are visibe to the naked eye on all but very small specimens. The
teeth of the lower jaw have narrow, erect cusps, the sides of which
are sub-parallel except near the tip. The teeth are slightly recurved
forward near the tip and the cusps are very finely serrate, the ser-
rations just visible to the naked eye on large specimens. The largest
tooth of the upper jaw of a six foot six inch male taken at Engle-
wood was 11 mm. from the tip to the enamel line. The largest tooth
of the lower jaw of the same specimen was 10 mm. from the tip to
the enamel line. The tooth counts of thirteen mature specimens of
14 2 15 15 3 15.
limbatus taken at Englewood run from -1 to 15 1
13 2 14 15 1 15
Full term embryos, 540 mm. to 570 mm. long, were taken from an
Englewood specimen captured April fourteenth. The young and
half-grown individuals are common at Englewood except in winter.

12. Isogomphodon maculipinnis Poey. THE BLACK-TIP SITARK.
The species was described from Cuba and was common at Engle-
wood during January, February, and March 1938. Nothing further
appears to be known about the range. This species is very similar
in appearance to the preceding. It probably reaches a little larger

STooth of upper jawu
Very finely serrate .V
STooth of lower jaw,
without serration.'
FIG 12.-THE BLACK-TIP SHARK, Isogomphodon maculipinnis

size. Three males, taken at Englewood in January, were all be-
tmween seven, and seven feet six inches long.
Aside from the differences given in the key, maculipinnis may be
distinguished from limbatus by its more slender form, sharper and


longer snout, and more intense colors. These characters, however,
are unreliable, and apparently subject to some variation. Local
fishermen who have seen numbers of both species recognize maculi-
pinnis because it is "keener," the term probably referring to the trim
and streamlined appearance given by the pointed snout and the de-
finite color pattern.
The teeth are much smaller than the teeth of limbatus, the largest
tooth of the upper jaw of a seven foot male being 7 mm. from the
tip to the enamel line, and the largest tooth of the lower jaw of the
same shark being 6 mm. from the tip to the enamel line. The upper
jaw teeth are narrower than those of limbatus and the serrations are
just visible to the naked eye in large specimens. The lower jaw
teeth do not have the tip recurved forward as in limbatus and their
edges are entire. The tooth count of eight adult specimens taken
16 2 16 17 3 17.
at Englewood run from to 1
16 1 15 16 1 16
Neither embryos nor very young individuals have been seen.

13. Hypoprion brevirostris Poey. THE LEMON SHARK.
This large West Indian shark regularly goes up the Atlantic coast
as far as the Carolinas and is common on the west coast of Florida
at least as far north as Tampa.
It is a heavy bodied shark with large fins and a short, broad snout;
usually yellowish brown, but sometimes dark brown. There are no
spots or markings of color. The dermal denticles are large and
rough to the touch. The second dorsal fin is nearly as large as the
first dorsal. There is no interdorsal skin ridge and the origin of the
first dorsal is in back of the inner angle of the pectorals. The
species may be mature at about seven and a half feet and reaches a
length of about eleven feet.
The teeth have rather narrow cusps on broad bases. The upper
jaw teeth are a little wider than the lower and the edges of the cusp
are entire The bases of the upper jaw teeth are irregularly serrate.
The edges of both cusps and bases of the lower jaw teeth are entire.
Tooth counts of eight mature specimens of the lemon shark run from
14 2 13 15 2 15.
12 2 13 o 14 3 14
A large female was present in the shallow, salt-water creek ad-
joining Bass Biological Laboratory on June first, and was under
observation frequently for several hours before darkness. The fol-
lowing morning the large shark was gone, but young with open
umbilical scars were present. Two of these small specimens', taken


June second, were 624 mm. and 630 mm. long. The young were
frequently seen in the creek until July twelfth, but left shortly after.
Two specimens taken from the creek on the twelfth were 730 mm.

Lower tooth, nao serratW

FIG. 13.--THE LEMON SHARK, Hypoprion brevirostris

and 750 mm. long. Under the circumstances, I think it very likely
that only one litter was present in the creek, and it is probable that
an increase in length of 100 mm. the first month is normal. I have
records of new born specimens from shallow inlets on the west coast
of Florida south of Englewood in May, June, July, and September.
The lemon sharks make up a considerable portion of the catches
of the shark fishery. The hides, fins, and oil are of good quality
and the species reaches a large enough size to be worth handling.

14. Aprionodon isodon (Miiller and Henle). THE SMOOTH-
This species is evidently rare. At least it is uncommon in our
waters. According to Jordan and Evermann it has been taken from

Teeth of both Jav V
without serration

FIG. 14.-THE SMOOTH-TOOTHED SHARK, Aprionodon isodon

New York, Virginia, and Cuba. H. W. Norris secured several
specimens at Englewood, and I have collected three at Biloxi.


Radcliffe records one from Beaufort, and gives a good description
of it.'
The specimens I had were immature, and under two and a half
feet long. The species may be recognized by the smooth pointed
teeth, which are without serrations on the bases or cusps. The gill
slits are comparatively longer than in related species to be found
in our waters.

15. Sphyrna tiburo (Linnaeus). THE SHOVEL-NOSE SHARK.
This species is thought to have a world wide distribution. Prob-
ably specimens from one part of the world have not been compared
with series from another part of the world. These are bottom feed-
ing sharks and one would suppose that populations of them might be
isolated from one another by broad expanses of deep water. Com-
parisons would certainly be interesting.

[ \

Lower side of head

FIG. 15.-THE SHOVEL-NOSED SHARK, Sphyrna tiburo

There are so many conflicting bits of information about this
species and the hammerheads in the literature that I hesitate to add
confusion to the situation without being able to clear up some of
the points. Unfortunately, about all I can contribute is the opinion
that there are more species than have been recognized, and that the
relationships within the family cannot be cleared up until compari-
sons of series of specimens are made.
The question of genera to which the various forms should be
referred may best be left until species have been more adequately
defined. The shovel-nosed shark has been placed in Gill's genus
Reniceps by some authors, and the older name of Swainson,
Platysqualus, has been used to harbour the great hammerhead on
the grounds that Swainson's reference to a figure in Russell depicts
the great hammerhead. However, Swainson describes Platysqualus,

S"The Sharks and Rays of Beaufort, North Carolina," Bulletin U. S. Bu-
reau of Fisheries, Vol. 34 (1914), pp. 252-3.


"Head more or less heart-shaped" and, by no stretch of the imagi-
nation can I see how that could be applied to the great hammerhead,
either more or less. Heart-shaped has frequently been used to de-
scribe the head of the shovel-nose. The description, then, is definite
and diagnostic. Judgments about the intent of Swainson seem use-
less. We evidently have two parts to the description which are in
conflict and one of them must be thrown out. It would seem the
better policy to use the part of the description that Swainson himself
produced, and if a separate genus is required for the shovel-nose
sharks, Platysqualus of Swainson should be used. In the characters
of skull shape and tooth form, the Florida west coast shovel-nose is
closer to the smaller Florida hammerhead, a form which I tentatively
call Sphyrna zygaena (Linnaeus), than to the great hammerhead
Sphyrna tudes (Cuvier).
The shovel-nose sharks may easily be distinguished from the ham-
merhead sharks by the characters given in the key. The
following discussion refers only to specimens collected at Engle-
wood, and undoubtedly all of the same species. The largest speci-
men in the lot of several hundred I have seen from Englewood was
110.0 cm. long (432 inches). The tooth count of ten adult speci-
12 1 12 14 1 14.
means runs from 1 1- 2 to13 The teeth of the upper
jaw have rather low pointed cusps, very oblique, and with the points
directed toward the angles of the jaws. The cusps of the last two
or three rows of teeth toward the angles of the jaws have very low
cusps or the cusps are entirely absent. The lower teeth are similar
except that the cusps are more nearly erect and the last four rows of
teeth have cusps extremely small or absent. None of the teeth have
serrate edges.
At most seasons, specimens up to three and a half feet are common
at Englewood, but I have no record of midsummer captures. An
examination of stomach contents has shown that crabs form a large
part of the diet.

16. Sphyrna zygaena (Linnaeus). THE COMMON HAMMERHEAD.
The Florida form of the common hammerhead may be readily
separated from the great hammerhead by the characters presented
in the key. Attention is particularly called to the shape of the sec-
ond dorsal fin. The very long posterior lobe on the relatively low
fin is characteristic and a reliable field mark.
16 0 16
The teeth are never serrate and are usually in rows.
15 1 15


The upper teeth are oblique and narrowly triangular, with the points
directed toward the angles of the jaws. The margins of some of
the teeth are curved so that the points are directed straight out from
the jaw. The lower teeth are slender and are more erect.
Nasal grove, deep. ,
*.resohe.3 are 40Aithout serration

Second dorsal fin.X

Aeal fin.

Fri. 16.-THE COMMON HAMMERHEAD, Sphyrna zygaena
The common hammerhead is more abundant at Englewood in
winter and specimens of all sizes up to nine feet have been taken.
No embryos have been collected. A few young individuals have
been secured in the late spring.

17. Sphyrna tudes (Cuvier). THE GREAT HAMMERHEAD.
At least a part of the original description of Sphyrna tudes ap-
plied to specimens collected at Cayenne but Mediterranean speci-
mens are mentioned as well. The plate accompanying the descrip-
tion in "Memoires du Museum d'Histoire Naturelle," M. A. Valen-
Nasal groove very shallow, long. Teeth of both jaws serrate.
..Nostril. Second dorsal fin.

I \ I

FrI. 17.-THE GREAT HAMMERHEAD, Sphyrna tudes
ciennes, Paris, 1822, pl. II, fig. la & lb, is a poor illustration of the
Florida Sphyrna tudes, and it may represent one of the Mediter-
ranean specimens. Compared with the illustration, the Florida
form has the mouth further back and larger. In Florida tudes, a
line through the angles of the mouth is posterior to a line along the


posterior edge of the hammer. The anterior edge of the hammer
in the illustration is more curved, the eyes are further forward and
smaller, and the nasal groove is depicted as more prominent than in
Florida specimens.
The great hammerhead probably reaches a much greater size than
the common hammerhead. Thirteen foot specimens are often taken
and there seems to be reliable evidence that fifteen foot individuals
have been secured. Apparently the species is not mature at less than
ten feet long. No great modification in form has been noted during
growth except that the hammer becomes more exactly transverse in
old adults, much more so than in adults of the common hammerhead.
The relative positions of the fins seems to be variable in this species
as well as in the common hammerhead and the shovel-nose.
The teeth of the great hammerhead are larger, in specimens of
the same size, than the teeth of the common hammerhead. They are
always serrate in both jaws, and the bases are very heavy. Tooth
17 2 17,
counts in most of the Englewood specimens have been 16 3 16
with variations of plus or minus one from each figure of the
At Englewood, the great hammerhead is more abundant in sum-
mer and large specimens have not been taken in winter. Three
females with embryos have been taken, all in early June. Of these,
a twelve foot specimen contained 30 embryos, and two thirteen foot
specimens carried 37, and 38 embryos respectively.

18. Rhineodon typicus Smith. THE WHALE SHARK.
The whale shark is' an enormous shark of the open seas. E. W.
Gudger has recorded specimens from the coast of Florida where it

FIG. 18.-THE WHALE SHARK, Rhineodon typicus
apparently is about as common as anywhere else. I have not seen
one. Dr. Gudger, in various papers, has given about all that is
known of the species.


19. Alopias vulpinus (Bonnaterre). THE THRESHER SHARK.
This species is not common in Florida waters. I have seen one
small one said to have been taken near Miami. I collected one
specimen of moderate size at Biloxi, Mississippi.

FIG. 19.-THE THRESHER SIARK, Alopias vulpinus

20. Odontaspis littoralis (Mitchill). THE SAND TIGER.
Two of these big ugly sharks have been taken at Englewood, one
specimen nine feet two inches long, and the other ten feet five inches
long, on February eighth and March thirteenth. They are often
taken on the east coast at all seasons, appearing irregularly in con-
siderable numbers off Salerno. I have compared our specimens
with a small one, sent to me by Mr. Breder of the New York
Aquarium, and can find no noteworthy differences. Evidently, only
the large specimens have been taken in south Florida waters and only
small specimens on the northeast coast of the United States.

FIG.' 20.-THE SAND-TIGER, Odontaspis littoralis

The sand tiger bears a superficial resemblance to the lemon shark,
but the snout is sharp pointed and the color is usually gray instead
of brownish. In both, the second dorsal fin is comparatively large,
nearly as large as the first dorsal. The teeth of the sand tiger are
very long, slender, and sharp, with small accessory cusps on either
side of the main cusp. There may also be rudiments of third cusps
on either side. None of the teeth are serrate. The central ones in
both jaws are long, in the ten foot five inch specimen the longest


tooth is 30 mm. from the tip to the enamel line, the lateral ones are
very short, almost paved. The teeth are similar in both jaws. The
fourth lateral teeth, counted from the symphysis, in the upper jaw
are small, and the first laterals of the lower jaw are small. At least
two series and sometimes three are functional. The tooth counts of
19 4 4 20 19 4 4 18.
the two Englewood specimens are--- 2 and
21 1 1 20 17 1 1 16
A single jaw from Salerno in my possession has the tooth count
17 3 4 16.
17 3 4 16. These three counts indicate a wide variation in
15 1 0 15
the tooth formula.The bases of the sand tiger teeth are hard, much
harder than in any of the sharks of the family Carcharinidae and
similar to those of the mackerel sharks and great white shark in that
Both the Englewood sharks were adult females but neither car-
ried embryos. When these sharks were captured both of them were
enormously distended and on opening them we found that the
stomachs contained bony fish, probably a hundred pounds in each.
There were a large number of the shark remoras, Echeneis nau-
crates, small Pogonias cronis, Menticirrhus sp. and Chaetodipterus
faber. Among the species of fish represented by a few specimens
were Cynoscion nebulosus and Mugil cephalus.

21. Isurus oxyrinchus Rafinesque. THE MAKO SHARK.
No mackerel sharks have been taken or sighted at Englewood. I
have one set of jaws from off Havana which probably were taken

Typical tooth.
FIG. 21.-THE MAKO SHARK, Isurus oxyrinchus
from a specimen of this species, and there is a cast in the Pfleuger
Museum in Miami of a specimen which I believe should be referred
to Isurus oxyrinchus. Isurus tigris (Atwood) is supposed to be
present in the Gulf of Mexico, although it would probably not often


be found in the shallow shore waters of the Florida west coast.
Isurus punctatus (Storer) may also occasionally appear in Florida
These are primarily fish-eating sharks, swift, powerful species of
the open sea. They may be distinguished from other sharks except
the great white shark (also a mackerel shark or member of the
-mackerel shark family) by the presence of a strongly developed
lower caudal lobe, making the tail-fin nearly symmetrical.
22. Carcharodon carcharias (Linnaeus). THE GREAT WHITE
One of these was taken by Mr. Holbrook and Mr. Green at Long
Beach near Sarasota in the winter of 1936-1937 and a second speci-
men was taken by them the following winter. From a photograph, I
judge that the second specimen was about fifteen feet long. A num-

Tooth of lower aw, Tooth of upper Jaw,
serrate. A serrate.

FIG. 22.-THE GREAT WHITE SHARK, Carcharodon carcharias
her of the teeth were collected at the carcass dump of the Salerno
shark station but Mr. Mooney tells me that these teeth must have
come in in the stomachs of other sharks. It is possible that the
species is much commoner than captures suggest. The species may
be recognized by the characters given in the key.


FIG. 23.-THE SPINY DOGFISH, Squagl acanthias


23. Squalus acanthias Linnaeus. THE SPINY DOGF[SH.
The spiny dogfish was recorded from the Indian River by Ever-
mann and Bean. I have no doubt that the species is occasionally
present in large numbers in deep water off the east coast of Florida
in winter.


1. IF THE SHARK has no anal
fin ....................----------.----------IT IS A SPINY DOGFISH
Squalus acanthias
an anal fin --------------------------REFER TO NO. 2
2-from 1. IF THE SHARK has
no nasal cirri ---------------------REFER TO NO. 3
pair of nasal cirri (small cy-
lindrical feelers in front of the
mouth) ------------------------.IT IS A NURSE SHARK
Gingylostoma cirratum

3-from 2. IF THE SHARK
has the mouth opening below
the tip of the snout, i. e., in-
ferior .------------------------- REFER TO NO. 4
the opening at the tip of the
snout, i. e., terminal ..----.... IT IS A WHALE SHARK
Rhineodon typicus

4-from 3. IF THE SHARK
has teeth with sharp points or
cutting edges .-------.-----.---.-. REFER TO NO. 6
blunt paved teeth without
sharp points or cutting edges..-.REFER TO NO. 5
5-from 4. IF THE SHARK
has the tip of the lower lobe
of the tail pointed, and if the
mouth is strongly arched in
front with its jaws forming an
angle of 90 degrees or less ....IT IS A GULF SMOOTH HOUND
Mustelus norrisi
the tip of the lower lobe of the
tail rounded, and if the mouth
is not sharply arched in front,
and forms an angle of more
than 90 degrees ------------.---.IT IS A COMMON SMOOTH HOUND
Mustelus canis


6-from 4. IF THE SHARK
has a symmetrical tail fin, with
the lower lobe nearly as large
as the upper lobe -----------------------.REFER TO NO. 7
an asymmetrical tail, with the
upper lobe much larger than
the lower lobe --------------......--------REFER TO NO. 8

7-from 6. IF THE SHARK
has broad, triangular, heavily
serrate teeth in the upper
jaw -----------------....... .. ...-.......... IT

long slender teeth, without ser-
rate edges ------------.-----.----.......... IT

Carcharodon carcharias

Isurus oxyrinchus
or one of the other mackerel sharks

8-from 6. IF THE SHARK
has an unusually long tail
which is more than one-third
the total length of the shark.---IT IS A THRESHER SHARK
Alopias vulpinus
a shorter tail, less than one-
third the total length of the
shark -------------.......-..................REFER TO NO. 9
9-from 8. IF THE SHARK
has the head expanded later-
ally to form a hammer or spade
shaped part -------------------------.---... REFER TO NO. 10
not have the head so expanded, REFER TO NO. 12
10-from 9. IF THE SHARK
has the anterior and lateral
margins of the head forming a
continuous curve, and the head
is spade shaped ........---............IT IS A SHOVEL-NOSE SHA


Sphyrna tiburo
the anterior and lateral mar-
gins of the head meeting to
form a definite angle, and the
head is roughly hammer-
shaped .-...-------.....................REFER TO NO. 11
ll-from 10. IF THE SHARK
has the posterior lobe of the
second dorsal fin short, so that
when it is lifted straight up-
ward, it will reach only a little
higher than the upper tip of
the fin; and if the teeth are
serrate -------.......... ---...............IT IS A GREAT HAMMERHEAD
Sphyrna tudes


the posterior lobe of the sec-
ond dorsal fin long, so that
when it is lifted upward it will
reach a point about twice as
high as the fin; and if the
teeth are not serrate .......---.. IT IS A

Sphyrna zygaena

12-from 10. IF THE SHARK
has the second dorsal fin nearly
as large as the first dorsal fin, REFER TO NO. 13
the second dorsal fin small, half
or less than half the size of the
first dorsal fin --.--............----.---REFER TO NO. 14

13-from 12. IF THE SHARK
has a pointed snout, and if its
long slender teeth have small
toothlets on either side at the
base --------------------------....---...... IT

a broad rounded snout, and the
teeth have no small cusps on
either side of each large one, IT

14-from 13. IF THE SHARK
has spiracles; and has large,
flattened, strongly serrate teeth
with the points directed to-
ward the angles of the jaws,
and if the teeth are similar
in both jaws ......... ............. --------- IT

Odontaspis littoralis

Hypoprion brevirostris

Galeocerdo arcticus

no spiracles; and if the teeth
are not as described for the
tiger shark -------------------.......----------REFER TO NO. 15

15-from 14. IF THE SHARK
has long labial folds, grooves
in the skin running forward
from angles of the mouth for
a distance of not less than one-
fifth of the width of the mouth
(measured from angle to
angle) ---..----------- ....-----------.... IT IS A SHARP-NOSED SHARK
Scoliodon terra-novae
short labial folds or none ........REFER TO NO. 16
16-from 15. IF THE SHARK
has slender, pointed teeth, with-
out any serration at all (slide
a sharp knife along the side


of the teeth of the upper jaw
to feel them if you cannot see
them) .--.-----.....---.....-- .----.IT IS A SM.OOTH-TOOTHED SHARK
Aprionodon isodon
any serration at all on any of
the teeth -.....--- ...----......-------REFER TO NO. 17
17-from 16. IF THE SHARK
has the teeth of the upper jaw
flattened and broadly curved
on their outer and inner mar-
gins, forming a tooth like the
tip of a curved saber .......------I---T IS A GREAT BLUE SHARK
Prionace glauca
teeth not so formed, and either
triangular, notched on the
outer margin, or erect and
slender .......--......-----------------....-REFER TO NO. 18

18-from 17. IF THE SHARK
has a ridge in the skin, run-
ning at least partway between
the first and second dorsal
fins -.................................- REFER TO NO. 19
no trace of a ridge ---------...--....- REFER TO NO. 20
19-from 18. IF THE SHARK
has the origin of the first dor-
sal fin in back of the angle
formed by the free inner mar-
gin of the pectoral with the dis-
tal margin (inner angle of the
pectoral) ---................-------------IT IS A DUSKY SHARK
Carcharinus obscurus
the origin of the first dorsal
fin in advance of the inner
angle of the pectoral --------.....---IT IS A SAND-BAR SHARK
Carcharinus milberti
20-from 18. IF THE SHARK
has the pectoral fins tipped with
darker color, and has the teeth
of the upper jaw neither
broadly triangular nor sharply
oblique and notched on the
outer margins -------............-----REFER TO NO. 21
not have the pectoral fins tipped
with darker, and has the up-
per teeth either broadly tri-
angular or sharply oblique and
notched on the outer margins, REFER TO NO. 22


21-from 20. IF THE SHARK
has the origin of the first dor-
sal over, or in advance of the
inner angle of the pectoral;
and if the teeth of the lower
jaw (of full grown specimens)
have some slight serration ----IT IS A

the origin of the first dorsal in
the back of the inner angle of
the pectoral; and if the teeth
of the lower jaw of full grown
specimens have no serrations, IT IS A
22-from 20. IF THE SHARK
has the snout very broadly
rounded, without a black tip;
and has the teeth of the upper
jaw erect and broadly trian-
gular ........................-. .........-- IT IS A

the snout somewhat pointed,
and has a black spot or smudge
-on the tip; and if it has the
teeth of the upper jaw ob-
lique, with the points directed
toward the angles of the
mouth .......-......... ... ........-IT IS A

Isogomphodon limbatus

sogomphodon maculipinnis

Carcharinus platyodon

Carcharinus acronotus


Florida State College for Women

The piece of research here reported was carried on in the psycho-
logy laboratory at the Florida State College for Women during the
regular session of 1937-38. It was the outgrowth of a desire to
determine the dependability of a current theory in parapsychology
and to provide material meaningful to further scientific investigation
in the field of extra-sensory perception.
The literature in the field of parapsychology is extensive, but few
adequately controlled experiments can be cited. Reliable scientific
evidence on any phase of psychic research, including extra-sensory
perception, is exceedingly meager.
As has been pointed out by Moore' in his review of the work in
the extra-sensory field, the evidence for the existence of "mental
telepathy" and "clairvoyance" is questionable as yet. He mentions
the fact that methods for investigating the phenomena of extra-
sensory perception are not standardized nor agreed upon. He feels
that at the present stage of the investigation an agnostic position is
the logical one to take-an attitude of not knowing. "Well planned
research in this field should be encouraged. The white light of
truth will expose the faker and the incompetent investigator no mat-
ter which side of the question he takes."
The most widely publicized and most extensive experimentation
in extra-sensory perception has been carried on by J. B. Rhine at
Duke University. In his book,' Rhine defines the statistical limits of
extra-sensory perception, and, in the light of this definition, advances
the theory that extra-sensory perception becomes more apparent in
extended series of discrimination. The following excerpt (p. 167)
will exemplify the theory which Rhine advances:
Above all, one must not, like several investigators, stop with only 25 or 50
or even 100 trials per subject. Most of my good subjects did not do very
well in the first 100. With few exceptions, the first 50 to 100 trials give the
worst scores. With all my major subjects this is true.

'Moore, J. E., "Is There Anything to Mental Telepathy?" Peabody Journal
of Education, Vol. 15 (1937-38).
'Rhine, J. B., Extra-Sensory Perception, (Boston: Bruce Humphries, 1935).


In the light of Rhine's limited data, his theory concerning the
shift in variation within an extended series of discrimination needs
verification under experimentally controlled conditions. Does the
theory, as he states it, find justification in fact when sensory cues
are entirely eliminated and when adequate statistical techniques are
applied to more extensive data? That is the question which this
investigation proposes to answer.
For the preliminary experiments 118 young women from the
classes in general psychology were employed as subjects. These
students, numbering usually between twenty and thirty to the group,
took part in the experiments during their regular class periods.
The subjects were seated in the regular laboratory class-room and
the experimenter was stationed in the next room, where the timing
device was also located. A thick wall separated the two rooms.
Both rooms opened on the hall and the heavy doors were closed
during periods of experimentation.
On the first day of the experiment a few preliminary remarks
were addressed to the various groups by the experimenter. These
remarks were brief and stated, in essence, that the positive character
of the results in the extra-sensory experimentation at Duke Univer-
sity had precipitated afresh the age-old controversy concerning
clairvoyance and telepathy. It was pointed out that the parapsycho-
logists at Duke were convinced of the reality of mental telephathy
and their criterion for the operation of extra-sensory perception was
a given deviation from chance expectation. It was also explained
that the object of the present investigation was to determine to what
extent the subjects would deviate from chance expectation in the
particular experiment set up, all sensory cues having been eliminated.
The preliminary remarks made to each group were essentially the
same and were offered for the purpose of creating interest in the
investigation. An open attitude was assumed by the experimenter
with regard to the results at Duke and with regard to the extra-
sensory field in general. Then the following directions were read
to the subjects:

This is an experiment in mental telepathy. I shall be in the next room and
at a given signal I shall concentrate upon one of these two symbols. (Hold
up the cross and the circle.) You will hear the signal at the same time and
will also concentrate in an attempt to determine whether I am thinking about
the circle or about the cross. We will concentrate for a period of 13 seconds
and then the buzzer will sound and you will record either a cross or a circle
in the space opposite the number for that particular trial. You will be allowed


3 seconds in which to record your decision. Then the buzzer will sound again
and the next period of concentration will begin immediately.
When the buzzer sounds for the first time it will be merely to show you
what the signal is like. Very shortly after the first signal the buzzer will
sound a second time. This is the signal for you to start concentrating. After
13 seconds the buzzer will sound again. This is the signal for you to record
your decision. After 3 seconds the buzzer will indicate the beginning of
the second concentration period and so on.

After the directions had been read, opportunity was given for
questions pertaining to them. Score sheets were distributed among
the subjects in order that they might record their own responses.
The chief piece of apparatus employed in the preliminary experi-
ments was a synchronous electric time clock. A metal brush at-
tached to a revolving hand projecting from the center of the dial
made contact with small brass plates along the outer rim of the dial.
Whenever the brush contacted one of the brass plates, two buzzers,
connected in parallel with the clock circuit, were sounded. The
brass plates were arranged at intervals of 14 seconds and 4 seconds
respectively. One buzzer was located in the room with the subjects.
Control of signalling was entirely automatic.
A table containing all apparatus except the one buzzer mentioned
above was located in the room with the experimenter. The mechan-
ical key used in checking responses and in determining the order of
the symbols to be concentrated upon by the experimenter was ar-
rived at by observation of the chance fall of two pennies shaken
from a box. These pennies were shaken up in the box half a
dozen times before being thrown out on the table and recorded as
alike (both heads or both tails) or as different (one heads and one
tails.) Three hundred throws of the pennies were made and re-
corded. The two possible combinations of patterns were found to
distribute themselves in precisely a 50-50 ratio; one hundred and
fifty times the pennies were alike and one hundred and fifty times
they were different.
The trials which had resulted in likeness were arbitrarily selected
to represent the circle, one of the symbols to be "sent" telepathically
by the experimenter. The trials which had resulted in difference
were likewise selected to represent the cross, the other symbol to be
"sent" by the experimenter. The three hundred results were then
typed on two sheets of paper, 150 to a sheet and 6 columns of 25
symbols on each page. The exact order in which the symbols had
empirically occurred was preserved, since the purpose in designing
such a key in the first place was to avoid "habits of thought" on the


part of the experimenter and to make possible an accurate statement
of normal chance expectancy as precisely 50-50. A "chance" dis-
tribution was thus obtained, "chance" in this instance bearing the
empirical rather than the theoretical connotation.
A small slot was cut in the center of a piece of white cardboard
of the same size as the key sheets. The slot was of just the right
dimensions so that when the cardboard was fitted over the key, one
symbol alone would appear simultaneously with the number for that
particular trial. The object of this precaution was to insure that
the attention of the experimenter would not be diverted by the mass
of symbols surrounding the one to be concentrated on at any given
moment. Moreover, this arrangement was of service in keeping
track of the correct place in the column.
Two cards from Rhine's regular ESP deck, a circle and a cross,
were employed as the symbols to be concentrated upon by the ex-
perimenter. These were selected because of their simplicity and
because they had apparently been found workable by Rhine.
The experimenter sat at a table in the adjacent room, facing a
blank, white wall. The electrical apparatus and the mechanical key
were located on this table. As soon as the key and the two cards
bearing the chosen symbols were arranged before the experimenter,
she started the timing device. At the sound of the buzzer the ex-
perimenter began concentrating on the card indicated by the mechan-
ical key for that particular trial. When the buzzer sounded again
she shifted the key to the symbol for the next trial. Approximately
150 trials were run at each experimental period of 45 minutes, a total
of 300 trials being taken for every subject. With 118 persons
participating, a grand total of 35,400 trials was run in the prelimi-
nary experiment.
When the 35,400 trials were completed, the results were checked
and rechecked by means of the mechanical key. The raw scores for
the 118 subjects were plotted in a frequency distribution. Project-
ing the parameters of the distribution against those of the Gaussian
curve as reference criteria of the error function, it was found that
the degrees of skewness and kurtosis were not significant. A test
of curve fitness gave a probability of one in five that the result
obtained was due to sampling errors alone. When the odds are five
to one against a random sample giving as great deviations as those
obtained, the error function of the normal curve may be used as a
function of the obtained curve, provided that the demands made
upon the derived limits of prediction by the coefficients of normal
ordinate displacement are duly observed. In the observed distribu-


tion, the number of degrees of freedom assigned to the variates from
theoretical mean expectation were determined without recourse to
conventional methods of condensation of tail frequencies. Use of
the latter methods of condensation would have provided a slightly
better fit than the one obtained.
Since the number of discrimination scored correctly by any one
student in the total distribution did not deviate significantly beyond
the fourth probable error, it is not possible on statistical grounds to
ascribe extra-chance characteristics to any individual performance
if we are willing to define the concept of chance in terms of the error
function criteria of the Gaussian curve.
In order to verify Rhine's theory that with practice a subject may
increase his number of correct discrimination, the twenty subjects
deviating to the greatest extent from normal chance expectancy were
selected to serve as subjects in the main investigation. Ten of these
selected to serve as subjects deviated in a positive direction from
chance, having made the greatest number of hits, and the other ten
deviated in a negative direction, having made the fewest number of
The control in this second experiment was essentially the same as
in the first experiment. The mechanical key and the two symbols
for concentration were employed again exactly as in the preliminary
The twenty subjects selected to take part in the main project were
interviewed individually by the experimenter. To each she pointed
out the fact that the subject was a member of the selected group
deviating to the greatest extent from normal chance expectation.
It was further pointed out that experimentation was being continued
for the purpose of investigating the trend of extra-sensory discrimi-
nations among this selected group over an extended series.
In view of the fact that many of the subjects were engaged in
various extra-curricular activities and in view of the fact that no
experiments could be conducted prior to 4:30 in the afternoon, it
was impossible to have every individual work at exactly the same
time every day. Instead, three periods of experimentation were
conducted daily, Monday through Friday, and any subject was free
to attend at any one of the three periods proving most convenient to
her on any particular day. However, no more than ten persons
were ever permitted to work at the same time. The experiment was
run from 4:30 to 5:00, 5:30 to 6:00, and 7:30 to 8:00 P. M., the
experimenter resting from the exigencies of concentration during
the intervening periods.


At each half-hour period 120 trials were completed by each sub-
ject. Approximately 2,000 trials were completed by the group each
day and approximately 10,000 trials were completed each week.
Make-up work was customarily handled on Saturday afternoons.
On the first day of the main experiment directions were again
read to the subjects. These directions were essentially the same as
those for the first experiment, with the exception that the time inter-
vals for concentrating and recording were reduced from 14 seconds
and 4 seconds to 10 seconds and 3 seconds respectively since several
students at the close of the preliminary experiment remarked that
the time allotted for reception and recording was longer than neces-
sary. Also attention was drawn to the fact that both a bell and a
buzzer would be employed in signalling, thus avoiding any confusion
resulting from the use of the buzzer alone. The remaining details
of the procedure were entirely similar to those of the preliminary
A total of 60,000 discrimination from all subjects was secured,
each subject having made 3,000 discrimination at the close of the
experiment. A frequency distribution of all 60,000 discrimination
was plotted and tested for normalcy against the parameters of the
Gaussian curve of errors. In terms of the chi-square test of curve
fitness, it was found that there are only 7 chances in 100 that the
chi-square obtained is attributable to some factor other than chance.
The probability of 93 in 100 indicates a statistically insignificant
degree of difference between the actual frequencies and the theoreti-
cal frequencies, and represents an excellent match between theory and
observation. The critical ratio expressed in terms of the probable
error to the specific error taken from theoretical mean expectancy is,
therefore, applicable to the empirical distribution for the purpose of
demonstrating sampling limits and the function of variance accord-
ing to the hypothesis in which 4 probable errors on either side of
the central tendency set off the limits within which chance fluctua-
tions are said to operate.
Approximately 25,000 more responses were obtained in the main
than in the prelimTnary experiment, and, whereas in the earlier in-
vestigation only 300 trials were given to each individual, precisely
ten times that number were given eachsubject during the main in-
vestigation. Hence, it is interesting to note that with an extended
number of categories the total response picture assumes a distribu-
tion whose chi-square is superlatively good rather than one whose
chi-square is only medium or fair as was the case with the earlier


A consideration of the individual histograms for each of the
twenty persons acting as subjects for the main investigation reveals
considerable variability in the configuration of individual perform-
ance. Chi-square values obtained for the individual distributions
range all the way from 51.3 where n is 14 to 10.4 where n is 15.
Despite this marked variation, it is to be remembered that the value
for P obtained from the chi-square for the total distribution of 60,-
000 responses is 0.93, considerably higher than that of the best (i.e.
most nearly normal) individual distribution. In other words, with
the addition of more scores the curve tends to smooth itself out and
to approach the ideal normal curve to a superlative degree.
Taking a score of 60 hits as expressing the theoretical mean ex-
pectancy of a single category of 120 individual discrimination made
by any given subject during any given experimental period, it is
found that in the total distribution of 500 categories only two cate-
gories extend 5% of the total distance of a single P. E. unit beyond
the 4th P. E. limit. The great bulk of the scores fall within 3 P. E.
(plus or minus) from normal chance expectation, 485 of the 500
categories resulting in scores lying within these limits and 419 of
them within the limits of 2 P. E. Scores falling between 3 and 4
P. E. on either side of the theoretical mean occurred in only thirteen
instances. In the two cases where the 4 P. E. limit was exceeded
it was not surpassed by the same individual both times, nor by a
distance which would be termed significant, the deviation being 15
units above or below theoretical chance expectation in either in-
stance, and the 4th P. E. extending to 14.8 units. It is interesting
to note that the deviation of +15 was obtained by a subject scoring
below chance in the preliminary experiment, and that the deviation
of -15 was obtained by a subject scoring above chance in the pre-
liminary trials.
In conclusion it may be stated that an evaluation of the data in
its entirety reveals no score which is not readily explainable in terms
of the chance hypothesis as based on the Laplace-Gaussian curve.
In the light of a discussion by Sorenson and in the light of the rule
of parsimony, an essential step in scientific interpretation, it is un-
necessary to posit any extra-sepsory factor to account for scores
made by any or all of the twenty subjects. Since the normal curve
has its limits theoretically approaching infinity and practically ap-
proaching the total range of achievement, the amount of the total
area extending the 5% of one P. E. beyond the 4th P. E. limit can

Sorenson, Herbert, Statistics for Students of Psychology and Education,
(New York: McGraw-Hill, 1936), p. 288.


not be regarded to have serious weight, either theoretically or prac-
In direct contradistinction to the theory advanced by Rhine, the
analysis of individual performance curves reveals no consistent
variation either in a positive or a negative direction within successive
categories. Those subjects who had scored high on the preliminary
experiments evinced about the same tendency toward sporadic, un-
predictable shift on successive periods as those who had scored low.
Hence, pure guessing is sufficient explanation of the results obtained.



SANFORD, SEMINOLE COUNTY-Fossils were dredged from Lake
Monroe by hydraulic dredges during the years 1926-32. Collecting
has been going on from 1926 to the present time. During high
water stages in the lake, wave action washes out fossils from the
hydraulic fill and they are then collected during low water stages.

Isorus sp.
Lamna sp.
Carcharodon sp.
Galeocerdo sp.
Hemipristis sp.
Glyphis sp.
Myliobatis sp.
Rhinoptera sp.
Enchodus sp.
Alligator miss;ssippiensis
Didelphis virginiana
Sylvilagus sp.
Castoroides ohioensis
Hydrochocrus pinckneyi
Procyon lotor
Lynx rufus
Mylodon harlani
H olnesina septentrionalis
Equus complicatus
Odocoileus osceola
Bison sp.
Mastodon americanus
Parelephas coluimbi
Trichechus sp.

Mackerel shark
Mackerel shark
Mackerel shark
Requiem shark
Requiem shark
Requiem shark
Eagle ray.
Eagle ray
Extinct family
Wrasse fishes
Tortoises and turtles
Giant beaver
Giant capybara
Harlan's ground sloth
Giant armadillo
Fla. White-tailed deer
American mastodon
Columbian mammoth
Sea cow

WEKIVA RIVER, SEMINOLE COUNTY-During the fall of 1934 three
local men while fishing in the Wekiva River observed through the
crystal clear water a large lower jaw lying on the sand bottom.
They dived over-board and after breaking it into several pieces suc-
ceeded in getting it into their boat. They then observed numerous



bones lying on the river bottom, scattered up and down the stream
for a distance of several hundred feet. As they were out of work
at the time they spent the next three weeks in recovering all of the
bones in sight. Approximately one-half of a mastodon skeleton
was recovered and two molars of a mammoth. Through the writer's
efforts these specimens are now owned by the Florida Geological
Survey. It is hoped that in the near future the balance of the
mastodon skeleton which is buried in the sand bottom of the river
will be recovered so that the entire skeleton may be mounted.

Tapirus sp.
Mastodon americanus
Parelephas columbi
Trichechus sp.

American mastodon
Columbian mammoth
Sea cow

OVIEDO, SEMINOLE COUNTY-During the summer of 1937 in digging
a pit for a WPA swimming pool the workmen encountered oyster
shell and clay in which were fragments of mastodon, horse and al-
ligator. The mastodon and horse are of Pliocene genera.

Alligator sp.
Hipparion sp.
Serridentinus floridanus

Fla. serrate-toothed

underlying Indian Shellmound at low water line fossils are washed
out by wave action.

Alligator mississippiensis
Castor canadensis
Euarctos floridanus
Megalony jeff ersonii

Mylodon harlani
Holmesina septentrionalis
Boreostracon floridanus
Equus sp.
Odocoileus osceola
Bison sp.
Mastodon americanus
Parelephas sp.

Fla. black bear
Jeffersonian ground
Harlan's ground sloth
Giant armadillo
Fla. glyptodont
Fla. white-tailed deer
American mastodon


DELEON SPRINGS, VOLUSIA COUNTY-Found in Pliocene shell pit.
The shell is excavated and used for road building purposes.

Lamna sp.
Carcharodon sp.
Galeocerdo sp.
Glyphis sp.
Myliobatis sp.
Rhinoptera sp.
Carnivora indet.
Proboscidean indet.

Mackerel shark
Mackerel shark
Requiem shark
Requiem shark
Eagle ray
Eagle ray
Wrasse fishes

SEMINOLE SPRINGS, LAKE COUNTY-Found in the bed of Seminole
Springs run. The shark and ray teeth are derived from Miocene
rocks that floor the bed of the stream near its source. The Pleisto-
cene fossils are washed in.

Ginglyinostoma serra
Isorus sp.
Latmna sp.
Carcharodon sp.
Galcocerdo sp.
Hemipristis sp
Myliobatis sp.
Rhinoptera sp.
Dictyodus sp.
Alligator sp.
Equus sp.
Tapirus veroensis
Odocoileus osceola
Bison sIp.
Mastodon americanus
Trichechus sp.

Nurse shark
Mackerel shark
Mackerel shark
Mackerel shark
Requiem shark
Requiem shark
Eagle ray
Eagle ray
Wrasse fishes
Tortoises and turtles
Fla. tapir
Fla. white-tailed deer
American mastodon
Sea cow

LEESBURG, LAKE COUNTY-During the building of the WPA
Venetian Gardens at Leesburg a hydraulic dredge was used to fill
in some low land. The following were found on the fill:

Alligator mississippiensis
Holmesina septentricialis
Parelephas columbi

Giant armadillo
Columbian mammoth


ROCK SPRINGS, ORANGE COUNTY-Found in the bed of the stream.
The shark and ray teeth are derived from the Miocene rock from
which the spring flows. -This rock also forms the stream bed near
the spring.

Galeocerdo sp.
Hemipristis sp.
Rhinoptera sp.
Alligator mississippiensis
Odocoileus sp.
Mastodon americanus
Trichechus sp.

Requiem shark
Requiem shark
Eagle ray
American mastodon
Sea cow

In 1889 Leidy (1) identified a Sabre-tooth tiger, Horse, Llama,
and an Elephant from a collection of teeth and bones collected by
Mr. Joseph Willcox from near Ocala, Marion County, Florida in
1888. The fossils were found in a clay filled crevice exposed by
quarrying operations in the Ocala limestone.
In 1916, Sellards (2) reported additional specimens collected by
the Florida Geological Survey from solution channels in the Ocala
Limestone near Ocala. The fossils were found imbedded in a sandy
clay matrix which represented material washed in from the surface.
In addition to the animals mentioned by Leidy he reported Rabbit,
Armadillo, Deer, and Bison.
In 1923, Hay (3), in addition to listing all of the above, added
Tapir based on a tooth that Mr. J. D. Robertson of Ocala had found
in a phosphate deposit near Ocala.
In 1929, Simpson (4) reviewed the Pleistocene mammals found in
or near Ocala in solution channels in the Ocala limestone. He listed
all previously mentioned by Leidy, Sellards and Hay, except the
Elephant recorded by Leidy. The reason for withholding the Ele-
phant is not apparent as Leidy described and figured two teeth (1).
During the past fifteen months E. J. Moughton, Jr., of Sanford,
Florida, and the writer have collected an extensive series of teeth
and bones from two localities near Ocala. In both cases the speci-
mens were found in a sandy clay matrix filling solution channels
in the Ocala limestone. The most important locality is at the mine
of the Dixie Lime Products Co. at Reddick, about fifteen miles north
of Ocala. The other is at the Cummer Lumber Co. mine at Ken-
drick, about five miles north of Ocala.
This collection adds to the previously recorded mammals from
near Ocala the following-Opossum, Mole, Shrew, Gopher, Mouse,
Rat, Bear, Wolf, Ground Sloth, and Peccary.



Scientific name

Didelphis virginiana .....
Scalopus aqualicus .---.....
Cryptotis floridana -------
Sylvilagus sp ...............
Sylvilagus floridanus ..
Sylvilagus palustris ..-
Geomys floridanus ........
Peromyscus sp...............
Oryzomys sp .............. ---
Sigmodon hispidus ....---
Arctodus floridanus ----
Canis ayersi ................
Smilodon floridanus' -
Mylodon harlani .....
Tatu bellas ...---..-
Equus leidyi ...............
Equus sp ..................
Taplirus sp.'
Odocoileus osceola .......
Odocoilcus sellardsiae
Platygonus sp. ............
Mylohyus sp.' .........
Tanupolana mirifica' .
Bison sp.' ....................
Parelephas sp ...........
1 Extinct.


Common name .

Opossum X
Mole x
Shrew x
Rabbit X
Fla. cotton tail X X
Marsh rabbit X
Fla. pocket gopher x
Mouse x
Rat x
Cotton rat x
Fla. short-faced bear x
Dire wolf x
Fla. sabre-tooth tiger X
Harlan's ground sloth X
Armadillo x X
Horse X x x
Horse x X
Tapir X x
Fla. white-tailed deer x X X
Sellard's deer x
Peccary x
Peccary X
Camel x x
Bison X
Mammoth x


1. LEIDY, JOSEPH. "Description of Mammalian Remains from a Rock Crevice
in Florida," Trans. Wagner Free Inst. Science, Vol. 2 (1889), pp. 13-17.
2. SELLARDS, E. H. "Fossil Vertebrates from Florida," Fla. Geological Sur-
vey, 8th Ann. Report, (1916), pp. 102-3.
3. HAY, OLIVER P. "The Pleistocene of North America and its Vertebrated
Animals, etc.,".Carnegie Inst. of Wash. Pub. No. 322, (1923), pp. 207 and
4. SIMPSON, GEORGE G.AYLORD. "Extinct Land Mammals of Florida." Fla.
Geological Survey, 20th Ann. Report, (1927-28), p. 271.

Bureau of Plant Industry, United States Department of Agriculture,
Julius Sachs, as early as 1880, clearly pointed out that the growth
of plants may be influenced by "specific substances" not of the na-
ture of foodstuffs. Twenty-five years later hormones were dis-
covered in animals, substantiating the principal point of Sach's
theory. The term hormone was derived from a Greek word meaning
"I arouse to activity" and was first used by Bayliss and Starling (1)
in referring to "those chemical substances secreted by the endocrine
glands which, when carried by the blood stream to another organ,
profoundly influence the activity of that organ."
It took another twenty-five years before botanists generally be-
came aware of the soundness of Sach's theory, but it is clear now
that plants do produce special substances which coordinate the activ-
ity of certain organs with that of others. These substances are ap-
parently not nutrients in the ordinary sense, but rather of the nature
of specific substances regulating growth.
Known chemical substances which are now regarded as plant
hormones include the "auxins" and the "vitamins." In both in-
stances the substances have been isolated from the plant tissues and
appear to have a regulating effect on some physiological process in
the plant. The physiological effects of these two groups of sub-
stances will be considered separately.


Isolation and identification of auxin.-A large portion of the
known facts about the auxins are based on work done on the cylin-
drical primary leaf sheath, or coleoptile, of Avena. In this organ
all cell divisions are completed at a very early stage, and subsequent
growth consists entirely of cell elongation. If the tip of the coleop-
tile is cut off, the coleoptile stops growing. Paal (23) demonstrated
that this is not due to a simple wound shock, for, if the tip of a de-
capitated coleoptile is replaced on the cut surface, the stump will
grow faster than without the tip. It therefore appeared that this in-
fluence of the tip was caused by some substance diffusing out of the
tip. Success in obtaining the active substance from the coleoptile


tips was finally achieved by Went (40). He placed the coleoptile
tips upon blocks of agar, and then placed the agar on one side of the
stumps of the decapitated coleoptiles. The result was a curvature
away from the agar block (See Fig. 1). He measured this curva-
ture, which was found to be proportional, within limits, to the con-
centration of the active substance. This test, "the Avena test," was
then used to determine some of the properties of the substance which
was shown to be thermostable, readily diffusible, and to have a mole-
cular weight of about 328.

[Abridged from illustration by Went and Thimann (43)
I 'I


I :

FIG. 1.--Diagrammatic summary of procedure in Avena test.
[Abridged from illustration by Went and Thimann (43)]
A.--A4vena coleoptile.
B.-Coleoptile decapitated leaving the primary leaflet protruding
above the stump.
C.-The primary leaf partly drawn out.
D.-Agar block with auxin placed on one side of cut surface,
resting against the leaf so that it is held in place by capil-
E.-Two hours after application of agar the resulting curvature
is measured.

The chemistry of various substances active in the Avena test was
worked out especially by KSgl, Haagen Smit and Erxleben (18) and
Thimann (31.). K6gl and co-workers isolated three different
crystalline substances, all giving positive reaction in the Avena test.


They have been named auxin A (C,,H32O,); auxin B (C,,HoO,);
and heteroauxin (indole-3-acetic acid C,oHON). Their chemical
structure is shown in Fig. 2. Auxin A and heteroauxin were
isolated from human urine and auxin B from malt and corn-germ
oil. Later Thimann (31) isolated heteroauxin from Rhizopus cul-
tures. K6gl and co-workers also have given good evidence by in-
direct methods that the active substance of the Avena coleoptile is
auxin A. It is also probable that other plants contain the same








FIG. 2.-Structural formulae for the auxins.

The three auxins are physiologically indistinguishable, all of them
giving the same type of growth and root production response. Also,
it is now known (44) that a number of other substances, such as
indolebutyric acid and napthyl-acetic acid, affect growth and root
formation in a similar way. These substances, however, have not
been isolated from plant tissue.


Auxin and Growth.-Results of Went (41) with Avena coleop-
tiles, Overbeek (22) with Raphanus hypocotyls, and Dijkman (10)
with Lupinus hypocotyls have shown that straight growth appears to
be strictly proportional to the applied auxin up to a clearly defined
limit, which limit varies for different plants. Applications of auxin
beyond this limit often result in swellings, and further growth in
length is inhibited.
In case of root growth, it has been shown repeatedly that certain
concentrations of indoleacetic acid such as promote growth of shoots
(1-10 p.p.m.) cause an inhibition of elongation of roots. It has,
however, recently been made clear by Thimann (33) that in the
presence of extremely dilute solutions (1/100 p.p.m.) roots of Avena
are slightly accelerated in their growth. Grace (13) reported
similar results for Salvia, lettuce, tomato, and nasturtium. Excel-
lent results were also obtained from treating germinating seed with a
hormone dust consisting of a dilute mixture of indoleacetic acid with
talc or a standard mercurial dust disinfectant. Wheat seed treated
with a 0.0002% indoleacetic acid preparation resulted in a 65% in-
crease in the length of the roots as compared with that on non-
treated seed.
Thimann and Lane (35) in a continuation of their study on the
response of roots of Avena to auxin has found that the plant soon
recovers from the inhibiting effect of a treatment with high auxin
concentration. The number of roots is increased and the general
vegetative growth of the shoot is accelerated. The leaves may be-
come both longer and wider, and the dry weight of the plant may
be increased more than 50 per cent.
Auxin and Root Formation.-Following the discovery of the
growth-promoting activity of the auxins, it was found that many
well known correlations in organ development are brought about by
the same substance. Sachs (27) assumed that root formation was
due to a special root-forming substance synthesized in the leaves.
Proof that a special substance produced by the leaves is indeed con-
cerned was obtained by Went (42) and the isolation of this active
substance by Thimann and Went (37) led to its identification with
the auxins by Thimann and Koepfli (34). This identity with the
auxins has been independently confirmed by many other workers.
Study of the use of indoleacetic acid for rooting cuttings of horti-
culturally important plants was begun by Cooper (7). He obtained
excellent root formation on cuttings of lemon, Acalypha and Lantana
by application of auxin in lanolin paste form to the tip of the cutting.
Later, the application of indoleacetic acid *in water solution to the


base of the cuttings was utilized successfully by Hitchcock and Zim-
merman (17) and by Cooper (8) for cuttings of many other plants.
Subsequently numerous other workers have obtained similar results
with thousands of different plants. Also Traub (38) has found
that a number of substances, which are not active in the Avena test,
are active in inducing root formation on cuttings. The furane com-
pounds and nicotine are examples of such compounds. Later, work
by Went (45) has suggested that these substances sensitize the cut-
ting, thus more or less preparing the way for the action of the nat-
urally occurring auxin in the cutting.
Auxin and Bud Inhibition.-Another phenomenon long known as
a typical correlation is the inhibitory effect of the terminal bud of a
shoot on the development of lateral buds [Goebel (12) and Reed and
Halma (25)]. The lateral buds, low down on a stem, do not
develop in presence of the terminal bud but if the terminal bud be
removed, some of the laterals usually grow out at once; this is
the basis of all pruning. Thimann and Skoog (36) were the first to
demonstrate that this inhibitory influence of the terminal bud is
nothing but the auxin produced by it. They removed the terminal
bud and put a dosage of indoleacetic acid on the stump. The buds
did not start to grow, but if the indoleacetic acid was removed the
lateral bud developed. Thus it appears that indoleacetic acid is
able to prevent buds from developing.
Auxin and Cambial Activity.-The one type of cell division which
appears to be readily controlled by auxins under physiological condi-
tions is the formation of, and division in, the cambium. Snow (29)
obtained excellent cambial activity in Helianthus hypocotyls by ap-
plication of pure auxin A and indole-3-acetic acid in concentrations
comparable to that occurring in the normal plant. He produced evi-
dence that the auxin formed the cambial activity below them.
The stimulation of cambial divisions in trees by auxin has been
studied by S6ding (30), who showed that insertion of a crystal of
indole-3-acetic acid into the cambium of woody twigs gives rise to a
rapid growth of new secondary wood. Brown and Cormack (5)
also found that the application of indole-3-acetic acid in lanolin
(1 p.p.m.) to the distal end of disbudded cuttings of leader shoots of
balsam poplar (Populus balsamifera) stimulated cambial activity
for a distance of 1.0-1.5 inches below the point of application.
A comprehensive study of the histological reactions of bean and
tomato plants to indole-3-acetic acid has been conducted by Kraus,
Brown, and Hamner (20), and Borthwick, Hamner, and Parker (4).


Seedlings were decapitated and a lanolin-indoleacetic acid mixture
(2 to 3%) was applied to the cut surface. In both plants many of
the tissues of the stem, in addition to the cambium, become meri-
tematic in response to the treatment, although most of the activity
was confined to a zone 0.5 to 2 mm. from the treated surface. The
cells of the cortical parenchyma, endodermis, phloem parenchyma
(both internal and external in case of the tomato), cambium, xylem
rays, and the pith exhibited the greatest activity. Little or no
meristematic activity, however, was found in the epidermis, most of
the pericycle, sieve tubs, companion cells, and internal fibers.
Auxin and Parthenocarpy.-Parthenocarpy, the production of
fruits without pollen, occurs naturally in a number of plants and has
been induced in others by a variety of means. Recently Gustafson
(14) obtained fruit development in several species, which normally
do not exhibit parthenocarpy, by applying lanolin mixtures of in-
doleacetic acid to the styles which had first been cut off close to the
ovaries. Fully developed fruits, without seeds, were obtained with
tomato, Petunia, pepper, and eggplant. Hagerman (15) reported
similar results with Gladiolus, and Gardner and Marth (11) pro-
duced parthenocarpic fruits on the American holly by spraying the
blossoms with aqueous solutions of indoleacetic acid.
From these results and other evidence obtained by numerous
workers, it appears that the pollen grain contains a growth promot-
ing substance (probably auxih), which may be carried by the pollen
tube to the ovary and cause it to grow.
Other Activities of Auxin.-A number of other effects of auxin
have been recorded. These include production of root nodules on
roots of leguminous plants (32), crown galls on Phaseolus (6), and
intumescences on leaves of Populus (21). It has also been shown
by Traub (38) that dilute solutions of either indole-3-acetic acid or
indole-3-butyric acid (1-10 p.p.m.) arrested senescence in fruits of
Passiflora and Citrus.
We have thus seen that the auxins play a varied role in the de.
velopment of plants, and influence a large number of processes.

Interest in the role of vitamins in plant development has centered
upon the water-soluble (B and C) rather than upon the fat-soluble
vitamins (A, D and E); so very little of the role of the latter is
known at present.
Vitamin BI is of general occurrence in the tissue of higher plants,
it having been found in leaves, stems, roots, fruits, seeds, etc. [sum-


mary in Sherman and Smith (28)]. The first direct demonstration
that B1 is a growth factor for higher plants was that of Kigl and
Haagen Smit (19). They used excised pea embryos grown in vitro
on a nutrient medium and found that added B, considerably im-
proved the growth of the embryos, even in concentrations as low as
10-8. The effect in this case was primarily upon the root, the
length, weight, and branching of which was considerably increased.
Bonner (2) and Robbins and Bartley (26) worked with the cul-
ture of excised roots in vitro and found that pea and tomato roots
will grow in vitro in an otherwise optimal nutrient solution only if
an adequate supply of B, is present. In other experiments with
green plants, it has been demonstrated by Bonner and Greene (3)
that the root is dependent upon the green leaf for its supply of this
vitamin, and the growth of many green plants may be limited by a
deficiency of B,. Aleurites, Buginvillaea, Arbutus, Eucalyptus,
Camellia, and Bryophyllum all showed considerably increased growth
from the application of an external supply of Vitamin B,. A similar
response was obtained for papaya in the U. S. D. A. laboratory at
Orlando. Furthermore, Bonner and Greene (3) have found that
organic manure contains appreciable amounts of Bx and conclude
that the beneficial effects of manure upon plant development may
be owing in part to its content of Vitamin B1. The B1 content of
the soil may be expected to be derived also from plant debris and
from soil microflora.
Vitamin C, also, is found generally in plant tissues. The work of
Virtanen et al., (39), and Ray (24) has shown that good growth of
the plant was correlated with a high vitamin C content. Later,
Havas (16a) was able to increase the growth rate of wheat seed-
lings by the addition of Vitamin C. Von Hausen (16) soaked pea
seed in a concentrated Vitamin C solution, then grew the seedlings
from such treated seed and found that seedlings from the treated
seeds increased in dry weight 35% faster than the controls. When
young plants were deprived of their cotyledons, the effect of added
vitamin C was even more striking.
Vitamin B1 is an essential part of one of the plant's oxidative
mechanisms and is very widely distributed in the plant. This vita-
min has a powerful growth promoting activity on young animals but
no marked effect of added B2 has been observed on the development
of higher plants other than that it appears to induce germination of
pollen (9).



We are now beginning to see the array of accessory growth fac-
tors which appear to be needed in minute amounts for the normal
growth of the higher plants. In this brief review only the effects of
known chemical substances have been considered. The existence
of many other specific substances, concerned with the development
of roots, leaves, flowers, etc., has been postulated, but the identity
of these substances with known chemical compounds awaits further


1. BAYLESS, W. M., and STARLING, E. H. "The mechanism of pancreatic
secretion," I. Physiol., Vol. 28 (1902), pp. 325-53.
2. BONNER, J. "Vitamin B1 a growth factor for higher plants," Science,
Vol. 85 (1937), pp. 183-4.
3. BONNER, J., and GREENE, J. "Vitamin B, and the growth of green plants,"
Bot. Gaz., Vol. 100 (1938), pp. 225-337.
4. BORTHWICK, H. A., HAMNER, K. C., and PARKER, M. W. "Histological
and microchemical studies of the reactions of tomato plants to indoleacetic
acid," Bot. Gas., Vol. 98 (1937), pp. 491-519.
5. BROWN, A. B., and CORMACK, R. G. H. "Stimulation of cambial activity,
locally in the region of application and at a distance in relation to a wound,
by means of heteroauxin," Can. Jour. Res., Vol. 15 (1937). pp. 433-41.
6. BROWN, N. A., and GARDNER, F. E. "Galls produced by plant hormones,
including a hormone extracted from Bacterium tumefaciens," Phytopath.,
Vol. 26 (1936), pp. 708-13.
7. COOPER, W. C. "Hormones in relation to root formation on stem cut-
tings," Plant Physiol., Vol. 10 (1935), pp. 789-94.
8. "The transport of root-forming hormone in woody cuttings,"
Plant Physiol., Vol. 11 (1936), pp. 779-93.
9. "Vitamins and the germination of pollen grains and fungus
spores," Bot. Gaz., Vol. 100 (1939), In Press.
10. DIJKMAN, M. J. "Wuchsstoff und geotropische Kriimming bei Lupinus,"
Rec. trav. bot. neerl., Vol. 31 (1934), 391-450.
11. GARDNER, F. E., and MARTH, P. C. "Parthenocarpic fruits induced by
spraying with growth-promoting compounds," Bot. Gaz., Vol. 99 (1937),
pp. 184-95.
12. GOEBEL, K. "Regeneration in plants," Bull. Torrey Bot. Club, Vol. 30
(1903), pp. 197-205.
13. GRACE, N. H. "Physiological curve of response to plant growth hor-
mones," Nature, Vol. 141 (1938), p. 3557.
14. GUSTAFSON, F. G. "Inducement of fruit development by growth pro-
moting chemicals," Proc. Nat. Acad. Sci., Vol. 22 (1936), pp. 628-36.


15. HAGERMAN, P. "Ober durch beta-indolessigsaure ausgeloste partheno-
karpie Gladiole," Gartenbauwissen schiift, Vol. 11, (1937), pp. 144-50.
16. HAUSEN, S. V. "Die Rolle des Vitamins C beim Wachtum der h6heren
Pflanzen," Biochem. Zeit., Vol. 288 (1936), p. 378.
16a. HAVAS, L. "Ascorbic acid and the germination and growth of seedlings,"
Nature, Vol. 136 (1935), p. 435.
17. HITCHCOCK, A. E., and ZIMMERMAN, P. W. "Effect of growth sub-
stances on the rooting response of cuttings," Contrib. Boyce Thompson
Inst., Vol. 8 (1936), pp. 63-79.
18. KOGL, F., HAAGEN SMITH, A. J., and ERXLEBEN, J. "Ober ein Phyto-
hormone der Zellstreckung," Zeits, physiol. Chem., Vol. 214 (1933), pp.
19. KOGL, F., and HAAGEN SMIT, J. "Biotin und Aneurin als Phytohormone,"
Zeitschr. Physiol. Chem., Vol. 243 (1936), pp. 209-26.
20. KRAUS, E. J., BROWN, N. A., and HAMNER, K. C. "Histological reactions
of bean plants to indoleacetic acid," Bot. Gaz., Vol. 98 (1936), pp. 370-
21. LA RUE, C. D. "Intumescences on poplar leaves. III. The role of
plant growth hormones in their production," Am. I. Bot., Vol. 23, pp.
22. OVERBEEK, J. VAN. "Wuchsstoff, Lichtwachstumsreaktion und Photo-
tropismus bei Raphanus," Rec. trav. bat. neerl., Vol. 30 (1933), pp. 536-
23. PAAL, A. "Ober phototropische Reizeitung," Jahrb. wiss. Bot., Vol. 58
(1919), pp. 406-58.
24. RAY, S. "On the nature of the precursor of the vitamin C in the vege-
table kingdom. 1. Vitamin C in the growing pea seedling," Biochem.
Jour., Vol. 28 (1934), p. 996.
25. REED, H. S., and HALMA, F. F. "On the existence of a growth inhibiting
substance in the Chinese lemon," Univ. Calif. Publ. Agr. Sci., Vol. 4
(1919) No. 3, pp. 99-112.
26. .RoBBIus, W. J., and BARTLEY, M. "Vitamin B1 and the growth of ex-
cised tomato roots," Science, Vol. 85 (1937), pp. 246-7.
27. SACHS, J. "Stoff und Form der Pflanzenorgane," Arb. bot. Inst. Wurz-
burg, Vol. 2 (1880), pp. 452-88.
28. SHERMAN, H., and SMITH, S. The vitamins. (New York Chem. Cata-
logue Co., 1931).
29. SNOW, R. "Activation of Cambial Growth by pure hormones," Nature,
Vol. 135 (1935), p. 876.
39. S6DING, H. "Ober den Einfluss von Wuchsstoff auf das Dickenwach-
stum der Biume," Ber. d. bot. Ges., Vol. 54 (1936), pp. 291-304.
31. THIMANN, K. V. "On the plant growth hormone produced by Rhizopus
suinus," I. Biol. Chem., Vol. 109 (1935), pp. 279-91.
32. "On the physiology of the formation of nodules on legume
roots," Proc. Nat Acad. Sc., Vol. 22 (1936), pp. 511-4


33. "On the nature of inhibitions caused by auxin," Amer. Jour.
Bot. Vol 23 (1937), pp. 561-9.
34. THIMANN, K. V., and KOEPFLI, J. B. "Identity of the growth-promoting
and root-forming substances of plants," Nature, Vol. 135 (1935), p. 101.
35. THIMANN, K. V., and LANE, R. H. "After-effects of the treatment of
seed with auxin," Amer. Jour. Bot., Vol. 25 (1938), pp. 535-42.
36. THIMANN, K. V., and SKOOG, F. "On the inhibition of bud development
and other functions of growth substance in Vicia faba," Proc. Roy. Soc.
B, Vol. 114 (1934), pp. 317-39.
37. THIMANN, K. V., and WENT, F. W. "On the chemical nature of the
root-forming hormone," Proc. Kon. Akad. Wetcnsch. Amsterdam, Vol.
37 (1934), pp. 456-9.
38. TRAUB, H. P. "Growth substances with particular reference to sub-
tropical fruit plants," Proc. Amer. Soc. Hort. Sci., Vol. 35 (1938), pp.
39. VIRTANEN, A. V., HAUSEN, S., und SAASTAMOINEN, S. Untersuchungen
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40. WENT, F. W. "On growth-accelerating substances in the coleoptile of
Avena sativa," Proc. Kon. Akad. Wetensch. Amsterdam. Vol 30 (1926),
pp. 10-19.
41. "Wuchsstoff und Wachstum," Rec. trav. bot. neerl., Vol. 25
(1928), pp. 1-116.
42. "On a substance causing root formation," Proc. Kon. Akad.
Wetensch. Amsterdam, Vol. 32 (1929), pp. 35-9.
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The Macmillan Co., 1937).
44. ZIMMERMAN, P. W., and WILCOXIN, F. "Several chemical growth sub-
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45. WENT, F. W., 1939. (In Press).

Florida State College for Women
In the summer of 1936 I gave little credence to the statement of
Carrie Yon Williams, a member of my Field Botany class, that
Torreya' was to be found west of the Apalachicola River on the old
Yon Plantation near Lake Ocheesee, Jackson County, Florida; for I
knew that that gently rolling country was not at all like the rugged
Torreya hills, cliffs, and ravines east of the river; moreover previous
explorations in Jackson County had always shown a singular lack of
many of the associates of Torreya of northern affinity or origin
found east of the river. So, of course, Mrs. Williams must have
been mistaken. Nevertheless, within a week specimens of Torreya
came fresh from Dog Pond on the present J. W. Yon property.
Present Distribution.-Now anything new concerning the distribu-
tion of Torreya is of interest and importance to students of plant
and animal distribution. It is not hard to account for this interest:
in past geological times Torreya was more or less widespread
throughout the Northern Hemisphere, but from the heart of this
area the species vanished in geological times. The genus, because
of its once greater past, its subsequent decline, and its final
local last stands, has always fascinated naturalists. Today only
remnant areas with four well established relic species remain:
Torreya californica Torr. in the mountains of California; Tor-
reya taxifolia Arn. in the Apalachicola River vicinity of Florida
and extending a mile or so into Georgia; Torreya grandis Fort.
in central and northern China according to Sargent.' and in eastern
China according to Rehder;' and Torreya nucifera Sieb. and Zurc. in

Among botanists: either Tumium taxifolium (Arn.) Greene, or Torreya
taxifolia (Arn.).
To tile public in general: Torreya.
Locally: Gopherwood, Savin, Stinking cedar, or Polecat wood.
'Sargent, C. S., Manual of the Trees of North America (3rd Ed.; Boston
and New York: Houghton Mifflin Co., 1933), pp. 1-910.
SRehder, Alfred, Manual of Cultivated Trees and Shrubs. (New York:
The Macmillan Co., 1927).


Japan. Sargent gives the Island of Quelpart as another station for
Torreya but does not say which species. Rehder recognizes a fifth
species, Torreya Fargesii, Franch. in central China and in western
China. There is some doubt of the fifth species. But in any event
great distances lie between any two of the species: Torreya taxifolia
and Torreya californica are separated by a Torreya-less stretch of
2500 miles; from Torreya taxifolia eastward across the Atlantic
Ocean, Europe, and Asia to Torreya grandis is about 8000 miles;
from Torreya californica across the Pacific, 6000 or 7000 miles; and
even the species conveniently dismissed as "Asiatic" it must be
realized may themselves be great stretches apart.

Past Distribution.-According to Boeshore and Gray fossil remains
of Torreya have been reported from Alaska (Cretaceous) ; Protec-
tion Island (Cretaceous'); British Columbia (Cretaceous); Oregon
(Eocene) ; California (Oligocene) ; Colorado (Cretaceous,); Geor-
gia (Cretaceous); North Carolina (Cretaceous); Virginia (Meso-
zoic); Greenland (Cretaceous and Tertiary); France (Pliocene);
and Silesia (Miocene). The fact that the species once flourished
over such an enormous area lends peculiar interest to the four or
five species remaining in as many isolated localities.
Because of this general interest and distributional significance I
explored the new location, on February 4, 1937, with the aid of
Mr. Penn King who acted as guide. The area was found to be
about an acre in extent and contained about sixty trees. All size
classes were represented from one foot high to fifty feet high and
ten inches in diameter at breast height. According to I. H. King
the colony was larger in former times but clearing adjacent forest
land for cultivation has reduced the stand to its present size. And
even now the habitat shows signs of burning, cutting, and disturb-
ance by hogs; yet there are seedlings of Tumion as well as sprouts.
But unless this colony is more violently and consistently abused the
species stands a fair chance of perpetuation even in this isolated and
maltreated spot.
On June 12, 1937 I made my third trip to the Dog Pond station
on the J. W. Yon property. At this time I collected specimens.
SBoeshore,, Irvin, and Gray, William D., "An Upper Cretaceous Wood:
Torreya Antiqua," American Journal of Botany, Vol. 23, No. 8 (October,
1936), pp. 524-528.


Several were sent to the Herbarium of the Florida Experiment Sta-
tion where they are now preserved as Specimen No. 26,668. On
July 6 specimens were sent to the Herbarium of the New York
Botanical Gardens and to the Herbarium of the University of
North Carolina. Receipt of each of these has been acknowledged.
Consultation of an early article by Chapman' revealed that fifty-
two years ago he had stated "there are, also, a few trees at the
southern extremity of Cypress Lake (now Lake Ocheesee) three
miles west of the river (Apalachicola River)." In fact he includes
a comprehensive, distributional map with Torreya hatched for the
south side of the southern end of the Lake as well as for the eastern
bluffs and tributary streams of the Apalachicola River.
It must be pointed out that Chapman's map of Cypress Lake is
far too simple, diagrammatic, and wholly inadequate to have any
value in placing or locating this colony of Torreya. It will be noted
that he hatches Torreya on the southern end of Cypress Lake. The
map of Ocheesee Lake in the present text is by C. A. Mahan,
draughtsman, after Bryan King, designer, both of the State Road
Department. Mr. King is a native of the region in question and,
therefore, we may consider his map of the Lake reasonably accurate.
A comparison of the two maps-Chapman's and the one of this
paper-shows at a glance how much Chapman was in error. The
colony is actually about six miles west of the Apalachicola River and
not three as stated by Chapman. Moreover, the colony is slightly
to the west of the south end of Dog Pond which in turn is south of
an arm projecting southward from the northwestern end of Lake
Ocheesee. Since we do not know which part of the very irregularly
shaped Lake Ocheesee his diagram represents, it is difficult to assert
just how far his hatched area would be from the actual location of
Torreya at Dog Pond, but it probably lies about three miles north-
west of Chapman's indicated area.
In spite of considerable exploration and consultation with local
residents I have as yet no verified record of Torreya in this vicinity
except the one at Dog Pond. This fact coupled with the inaccuracy
of his map and a statement quoted by Chapman elsewhere in this
paper make it hard to believe that he actually saw Torreya at Cypress
Lake. On what basis Chapman mapped the species where he did
is up to the present unknown to me.

"Chapman, A. W., "Torreya taxifolia, Arnott. A Reminiscence," Bot.
Gaz., Vol. 10 ( April, 1885), pp. 251-254.


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However, the following other considerations are also of interest.
Sargent' in speaking of Torreya taxifolia Am., says: "Western
Florida, eastern bank of the Apalachicola River from Chattahoochee
to the neighborhood of Bristol, Gadsden County; doubtfully reported
from the shores of a small lake west of Ocheesee and at Wakulla
Springs, Wakulla County. (Curtiss)." He quotes' Curtiss as fol-
lows: "There are two trees in this region of particular interest, as
they are not known to grow anywhere else; these are the stinking
cedar (Torreya taxifoliaz) and the yew (Taxus Floridana). There
is reason to believe that the Torreya occurs also along the Wakulla
River, and perhaps elsewhere in the state, but there is no positive
knowledge of its occurrence except along the Apalachicola River, on
the limestone hills which border it at intervals on the east." While
this volume was not published until 1884 Sargent wrote his manu-
script as early as 1880. So just about five years before Chapman's
statement and map or 1885 Sargent received but doubted the rumors
of the presence of Tumion west of the Apalachicola River. Still
more puzzling is the fact that Chapman himself confines Torreya to
"rich soil, eastern banks of the Apalachicola River, middle Florida"
in his revised book' published in 1897 twelve years after his article'
in the Botanical Gazette.
A number of others have written on the restricted distribution and
endemism of Torreya: Gray,' Curtiss (quoted in Sargent'), Nash,"
Cowles," and Harper," All of these, tersely said, have by

Sargent, C. S., "The Forests of the United States in their Economic As-
pects," Tenth Census of the United States, Vol. 9 (1884), p. 186.
'lbid., p. 521.
'Chapman, A. W., Flora of the Southern United States, (New York:
American Book Co., 1897).
'Gray, Asa, "A Pilgrimage to Torreya" The American Agriculturist, Vol.
34 (July, 1875), pp. 266-267.
SNash, George V., "Notes on Florida Plants II," Torreya Botanical Club
Bulletin, Vol. 23 (1896), pp. 95-108.
Cowles, H. C., "A Remarkable Colony of Northern Plants Along the
Apalachicola River, Florida, and Its Significance," Report of the Eighth
International Geographic Congress, (1904), p. 599
Harper, R. M., "The River Bank Vegetation of the Lower Apalachicola,
and A New Principle Illustrated Thereby," Torreya, Vol. 11 (November,
1911), pp. 225-26.
"Harper, R. M., "Apalachicola River Bluff and Bottoms. Geography and
Vegetation of Northern Florida," Fla. Geol. Survey, 6th Ann. Report
(1914), pp. 210-216.


omission or commission limited the tree to a relatively narrow, ir-
regular block of rugged topography on the east side of the Apala-
chicola from the Florida-Georgia line, but within Florida, to the
neighborhood of Bristol. Harper," by discovering a few trees
growing just over the Florida-Georgia state line near Chattahoochee,
extended the range of Torreya a mile or less into Georgia. Both
Sargent and Small recognize this extension by Harper. But the
same authors disregard Chapman's record of isolated trees stranded
near Lake Ocheesee, Jackson County about six miles west of the
river; Sargent states: "On bluffs along the eastern banks of the
Apalachicola River, Florida, from River Junction to the neighbor-
hood of Bristol, Liberty County, and in the southwestern corner of
Decatur County, Georgia (R. M. Harper)." Small says "bluffs
and woods along the Apalachicola River and tributary streams."
This statement of Small's, because of the omission of such terms
as "eastern bank" as used by Sargent, is broad enough to cover
any possible new stations of Torreya on either side of the river, yet
Small's retention of "tributary streams" makes the statement too
specific to apply to the distribution of Torreya west of the river, for
the known disjunctive Torreya station west of the river is far from
any tributary streams.

The strange fact that Chapman's record of these Torrcya
disjunctive outliers seems to have been consistently disregarded or
overlooked for fifty-two years justifies a re-birth of his distribu-
tional statements of 1885. Hitherto the records confine Torreya to
i more or less irregular strip of about 18 miles in length north and
south and varying eastward from the river. Its eastward extension
would naturally depend locally upon the size of the tributary streams
and their proportional valley bluffs. The maximum would probably
be under eight miles away from the river. The extension of this
extremely restricted species by five or six miles is therefore in itself
noteworthy; but there is still another interesting angle, and that is
the freakishness of this outlying colony. Here we have on the one
hand a species presumably very specific in its habitat, avoiding bluffs
which appear from a vegetative, topographical, and soil aspect just a

Harper, R. M., Tumion tarifolium in Georgia," Torreya, Vol. 19 (June,
1919), pp. 120-2.
Small, J K., Manual of the Southeastern Flora. (New York: Author,


continuation of the hills two or three miles farther north and east,
ward where it does grow; a species avoiding also a rather highly dis-
sected area in the vicinity of Quincy, 20 miles farther east where
many of its arboreal associates do grow. There is even no record
of the species on the hills a mile across the river nor is it found on
the natural levees adjacent to the banks east of the river which
harbor many of its tree associates of the bluffs. In fact, though it
does often invade the more nearly level adjacent terrain, it seldom,
if ever, ventures far into the level uplands bordering the river bluffs.
On the other hand the tree has moved six miles in the opposite direc-
tion across the river and established itself in an area of about one
acre, on soil only a few feet above the adjacent swamp and in a
locality devoid of bluffs or ravines and of the northern species as-
sociated with Torreya at the river.


Plant Associates of Torreya.-This Apalachicola River region con-
tains practically all arboreal species to be found in central and north
Florida besides some not found elsewhere. In addition many
northern species find their southernmost extension here. Cowles,"
Harper," and Kurz have pointed this out. A partial list of signif-
icant species often associated with Torreya follows. For conipari-
son the commonest species found with Torreya at Dog Pond are also
given. The nomenclature follows the usage of Small."

Actaea alba Osmanthus americana
Aesculus Pavia Ostrya zirginiana
Callicarpa americana Pinus glabra
Cercis canadensis Ptelea trifoliata
Dirca palustris Saccharodendron floridana (Acer)
Fagus grandifolia Symplocos tinctoria
Halesia diptera Taxus floridana
Magnolia grandiflora Trillium Underwoodii
Oakesiella floridana Tumion taxifolium

"Kurz, H., "Northern Disjuncts in Northern Florida," Fla. Geol. Surv.,
23rd-24th Ann. Report (1933), pp. 50-53.



Bignonia crucigera
Croomia pauciflora
Dentaria laciniata
Hepatica triloba
Mitchella repens
Muricauda Dracontium (Arisaema)

Sanguinaria canadensis
Smilax Bona-nox
Syndesmon thalictroides (Anemonella)
Toxicodendron radicans (Rhus)
Trillium lanceolatum


Cercis canadensis.
Fagus grandifolia
Halesia diptera
Ilex opaca
Magnolia grandiflora

Mitchelia repens
Anisostichus crucigera (Bignonia)
Smilax Bona-nox

Osmanthus americana
Ostrya virginiana
Pinus glabra
Symplocos tinctoria

Smilax pumfla
Toxicodendron radicans (Rhus)

Outstanding are the facts that not one of the rare northern herbs
of Apalachicola River is to be found at Dog Pond; that Dirca and
Taxus are also not here. In fact except for the Magnolia-Beech
forest species which are to be found anywhere in North Florida
where the mesophytic climax forest exists there is nothing in the way
of species that links this Torreya out here with the main area east
of the river.

Topography and Geology.-Chapman implies that the species is con-
fined to rugged topography: "To these cliffs, and to the precipitous
sides of these ravines, the tree seems to be exclusively confined; for
it is never seen in the low ground along the river, nor on the elevated
plateau east of it, nor, indeed, on level ground anywhere." In con-
sidering this statement one is forced to doubt that he really saw the
flat habitat of the Torreyas he maps for Lake Ocheesee. Sargent'
says: "there is no positive knowledge of its occurrence except along
the Apalachicola River on the limestone hills. ." In 1904
Cowles wrote: "It seems likely, then, that we should regard Tor-
reya taxifolia as a northern mesophytic left stranded today only in
Florida. It presumably is one of the plants that failed to follow up
the last retreat of the Pleistocene ice, and is preserved here perhaps


because of exceptionally favorable topographic conditions." Har-
per gives a good account of the geology, topography, hydrography,
soils, and vegetation in his "Apalachicola River Bluffs and Bot-
toms," He lists and indicates the relative abundance of one hundred
and fifty-one plants. Of the topography he writes: "The topog-
raphy is everywhere hilly, and dissected by numerous ravines and
small valleys, many of which end in amphitheatres or 'steepheads' at
the edge of the upland." It seems evident that rugged topography
is a favorable factor; it is equally evident from the Dog Pond habitat
as well as from the Apalachicola River region that great relief is not
imperative. 'Limestone as such, while favorable, must also be ruled
out, for even at the river Torreya thrives locally where limestone is
no nearer to the surface than it is locally at the Tallahassee Red
Hills, fifty-six miles east, nor any nearer than it is at Marianna,
twenty miles farther west.

Soils.-I took soil samples from one foot interval levels' to a
maximum depth of four feet, from three different Torreya localities,
namely Alum Bluff, Aspalaga, and Flat Creek, east of the Apala-
chicola River and from the new Dog Pond station. There were
some striking differences. The Alum Bluff samples were taken
from the side of a steephead; these samples consisted predominantly
of coarse sand. There were, possibly due to instability, no marked
zones of extraction (A-horizon), or concentration (B-horizon), and
of neither extraction nor concentration (C-horizon). The Flat
Creek samples on the other hand proved to be a much finer sand and
the A-, B-, and C-horizons were beautifully in evidence. At Aspa-
laga, in glaring contrast to the two former samples, the soil consisted
of clay and limestone pebbles, the rock being in places near the sur-
face. There were no A-, B-, and C-horizons here either. At Dog
Pond there were suggestions of A-, B-, and C-horizons. The soil
was predominantly light chocolate colored, silty sand. A table of
reaction follows:
ept Alum Flat Aspa- Dog
Depth Bluff Creek laga Pond
Surface 5.5, 5.0 5.0, 5.0 8.0, 7.5, 7.5 5.0, 50
1 foot 4.5, 4.5 5.0 7.0 5.0
2 feet 4.5 5.0 8.0, 7.5 5.0
3 feet 5.0 4.5 5.5
4 feet 5.0 4.0 4.0


A moment's consideration of these more obvious soil characteristics
leads to the disappointing conclusion that the distribution of Torreya
either east or west of the river is not to be explained by the absence
or presence of clay, sand, or humus; by the mesh size of soil parti-
cles; by definite or indefinite A-, B-, or C-horizons; nor by alkalinity
or acidity.
What the modern, exceedingly delicate and precise spectrographic
method of chemical analysis as applied to the soils or tissues of
Torreya would reveal is of course of tremendous interest and im-
portance here as well as in numerous other freakish plant distribu-
tional problems.

Geology.---A geological map by Cooke and Mossom shows that
most of the Torreya region east of the river is underlaid by Tampa-
limestone formation. However, Torreya grows several miles
farther south and nearer to Bristol than this limestone reaches.
The map is a generalized one and whether the limestone actually
does or does not go as far south as Torreya awaits more careful
exploration and mapping. A rapidly tapering and sinuous braid of
this same Tampa is mapped across the river and westward across
Jackson and into Washington Counties. That the Dog Pond colony
falls within this formation is of interest. That the Torreya-less
Tallahassee and Marianna Red Hills are not of the Tampa age is
also of interest. But until we have a more detailed and accurate
geological map and until the distribution of Torreya is more care-
fully worked out no conclusions having to do with Torreya distribu-
tion and geological formation can be drawn.
We can epitomize our habitat studies by saying that a considera-
tion and study of topography, soils, and underlying formations give
no conclusive common denominator for the main Torreya area east
of the river and the isolated colony at Dog Pond.

Torreya parallels Taxus.-Before summarizing I should like to call
attention to a similar isolation discovered for Taxus Floridana Nutt.,
a genus related to Torreya, and similarly endemic. This species
although very much rarer than Torreya (forty times Harper says ")
if found at all is usually with Torreya. Ten years ago, however, I
discovered Ta.vus in the water-logged, acid "Johnson's Juniper

Cooke, C. W., and Mossom, Stuart, "Geology of Florida," Fla. Geol.
Surm., 20th Ann. Report (1928), pp. 1-294.
"8Kurz, H., "A New and Remarkable Habitat for the Endemic Florida
Yew," Torreya, Vol. 27, No. 5 (Sept.-Oct., 1927), pp. 90-92.


Swamp" at least eight or ten miles south and completely isolated
from the mesophytic hardwood forest of the Bluffs. This isolated
and strange habitat for Taxus had even fewer species and factors
in common with the Apalachicola River Bluffs than the Dog Pond
Torreya station. From the standpoint of present ecological knowl-
edge no two habitats could be very much more in contrast than the
mesophytic ravines of the Apalachicola River Bluffs, where the yew
occurs rather sporadically, and this juniper (Chamaecyparis
thyoides) swamp. Thus it will be seen that Torreya taxifolia and
Taxus Floridana have been similarly projected from the main area
of concentration and have been randomly lodged into two disjunc-
tive spots strikingly different from each other and from the main
Torreya-Taxus region along the river. In these latter random spots
they persist for reasons now unknown.

Torreya's Habitat Prerequisites Unknown.-Statements have been
and still are made that Torreya is restricted to steep slopes and to
lime soil; that the species is waning; that it is reproducing by sprout-
ing only; and that seldom are seedlings seen. A careful review of
the environmental studies presented in this paper will disclose the
fact that if Torreya selects any obvious factors or set of factors we
have as yet been unable to ascertain just what they are.
Those who fear that Torreya is vanishing may be consoled by the
fact that there is no evidence to that effect. Indeed if the devasta-
tion of man could be eliminated the species would in all probability
be in no immediate danger. Its vegetative reproduction and many
seedlings and saplings that we have seen in spite of deforestation
and abuse attest that Torreya will require nothing for its survival
except a severe letting alone.

1. Chapman's long disregarded or overlooked approximate location
of Torreya at Lake Ocheesee, Jackson County across the Apala-
chicola River has been re-established.
2. The presence of more than sixty Torreya plants in this disjunct
station so dissimilar to its main and long known habitat or
habitats is almost as inexplicable as the disjunctive station
established by me for Taxus Floridana in 1927. As a matter
of fact, ordinary topographic features, soil peculiarities and
characteristics, water, and pH relations give no clue to its
habitat requirements anywhere. While it is true that Torreya
is partial to slopes and cliffs, it is by no means confined to them.


3. The fact that Torreya is confined mostly to or near the Tampa
formation on the east side of the Apalachicola River and also
in the new station is of interest, but at present I cannot say
whether this is of any significance.
4. Torreya produces enough sprouts and seedlings to insure its
survival provided only that man let nature alone in the Torreya

I am indebted to H. H. Hume, director of Research at the Florida
Agricultural Experiment Station, who made a number of original
papers available to me, and also to R. M. Harper, Alabama State
Geologist, who furnished quotations from papers not available to
me. To Mr. Bryan King of the State Road Department I am in-
debted for furnishing details of the outlines and localities of Lake
Ocheesee and Dog Pond. I must thank Mr. Autrey C. Mahan, also
of the State Road Department, for technical aid in the field and for
preparation of the map.

Florida State College for Women

Rivers and their environs present fascinating opportunities for
botanical studies. Here the nature lover usually finds many species.
and luxuriant plant life. One popular explanation of this abundance
of species is that the water of the stream or stream system itself
provides the vehicle and route for plant migration; that the seeds
and fruits collected up stream are floated down the valley, favorably
lodged here and there and left to germinate. Migration up the
valley against the current is not considered in this explanation.
A more plausible accounting for the variety of plant life of river
territory begins with a physiographic point of view. This explana-
tion recognizes the bars, banks, natural levees, spillways or runs,
oxbow lakes, flood-plains, river terraces, adjacent slopes, bluffs or
cliffs, and upland, as topographic features brought about by the work
of running water; it realizes, too, that each of the several physio-
graphic features offers a distinct combination of environmental fac-
tors. One set of factors may favor or permit foothold for one as-
sociation; and another set harbor a group entirely different. One
situation may be too wet for some species, another may be too dry;
in one place the unstable substratum may preclude some, elsewhere
the very stability may bar others. Bearing in mind these differences
in stability of substratum, and the extremes in soil composition and
content, one can readily see why river topography is so remarkable
in plant variety.
To return briefly to the problem of plant migration and distribu-
tion referred to above, plant ecologists hold that the abundance of
species in the vicinity of a river depends on the great variety of
conditions that running water brings about by the forces of erosion
and deposition. Of course, there must be migration, but water is
not the only agent of dispersal. To move seeds across land or up a
hill or across country, agencies like wind, animals, and even gravity
will often suffice. An important consideration in plant migration
is time. In a long period of time plants can and do migrate great
distances. How far they move year by year is not so important as


the number of years they have had in moving, and south of the
glaciated areas this time has run into millions of years.


Because of its endemic Torreya (Tumion taxifolia) and Florida
yew (Ta.vus Floridana) its flora of northern affinity, and its abun-
dance of other species the Apalachicola River has long been a sub-
ject of much interest and a number of papers. Harper' has pub-
lished an excellent general account of the geology, topography,
hydrography, soils, and vegetations of the area in the "Apalachicola
River Bluffs and Bottoms" section of his "Geography and Vegeta-
tion of Northern Florida." Listing one hundred and fifty species
he relates them to such habitats as "bottoms," "banks," "bluffs,"
"swamps," "richwoods," and so on. Harper's work is also valuable
for its references. Since Harper's publication, two papers '' have
been written by the present author dealing respectively with northern
disjuncts and a new station for Torreya. The latter paper also
briefly reviews some of the former works dealing with the Apalachi-
cola River flora.


In the discourse that follows the writer attempts to relate certain
tree and shrub species or societies of species to the topographic fea-
tures of the particular habitats that tend to harbor them. However,
the reader should be informed that from the very nature of the
problem it is impossible to arrive at inflexible generalizations. A
number of reasons can be given. In the first place the river area
shows everywhere the influence of lumbering and grazing so that the
virgin forest conditions are not at hand; one can only surmise what
would be, or tends to be, true by the relic trees or remnants of plant
associations found here and there. Secondly, the writer is not pre-
pared to deal with complications introduced by such catastrophic fac-

Harper, R. M., "Apalachicola River Bluff and Bottoms. Geography and
Vegetation of Northern Florida." Fla. Geol. Survey, 6th Ann. Rept. (1914),
pp. 210-216.
'Kurz., H., "Northern Disjuncts in Northern Florida," Fla. Geol. Survey
23rd-24th Ann. Report (1933), pp. 50-53.
3--, "The Effect of Cold Storage on Certain Native American
Perennial Herbs," these Proceedings, Vol. 2 (1937), pp. 36-52.


tors as fire. And finally, as any biologist knows, seldom do living
things behave unconditionally according to any ironclad formula;
not always do plants take advantage of or confine themselves abso-
lutely to particular habitats that may be considered suitable for them.
Nevertheless, because of the frequency with which they have been
observed, certain tendencies can be stated. It really is often possible
to predict that certain species or associations will be found in a
specific topographic situation or habitat.
The descriptions and conclusions of the subsequent pages are based
on a number of field trips to the eastern side of the Apalachicola
River in the vicinity of Aspalaga, Gadsden County, and Alum Bluff,
Liberty County, supplemented by a study of the east and west sides
of. the Chattahoochee River in the vicinity of Butler, Florida. The
following river transect is, then, really a generalized and recon-
structed one, representing the sum total of observations of a number
of duplicate habitats or topographic features.


Interior Upland.-Here the erosive effect has been relatively slight.
A mantle of sterile sand accumulated, or still lies, as the case
may be, over the underlying clay or decomposed rock. This particu-
lar area of the transect is characterized by long leaf pine and four
species of scrub oaks.

Adjacent Uplands.-The immediately adjacent upland more exposed
to the erosive work of the river nearby shows clay or even partially
decomposed rock outcropping, or at least near the surface. The
soil here, approximating a loam, supports a red oak-white hick-
ory-short leaf pine forest.

Unstable Slope.-A slope may locally present a variety of physio-
graphic features. The latter in turn may be characterized by very
different plants. The convex side of the curve of a stream, if the
geological strata are non-resistant, is often bordered by a more or
less sliding mass of clay, sand, or gravel known as a talus slope. On
such a raw and creeping substratum only certain plants can exist.
At Alum Bluff, for example, pines, sourwood, and wax myrtle were
most prominent. Here and there seepage waters form soft, wet,
and unstable habitats, where only certain species adapted to such
conditions can survive. However, the very talus slope in question
presents many peculiar conditions demanding more investigation.




Ccrnus Florida SLOPE
Diospyros vigiamna OXBOW TIDD-PLAIN LEVEE
Hioria alba Dirca patustrls
Nyssa. sylvatica Hydrancea- cinerea Cephalanthus codaitsAcep negsrndo Bumelio. lycioides
Rnus echinata Hcdranea qeraFeL Gleditia .auatica Carpinus carolnis.Halesia- car-olina
i nus Teeda toreya to axifolIa Itea viri tca Celts misssesippiensisHicola. coodiformnis
Quercus lauvifoha Ny sea Oeche nrnxinus nericas. Jtugl1an 19ige
Quercus stellata. SFECIE3 SL e- t.ZLE sesa unifloro. Hicoia aquatic Ulmus alva.
Quercus velutina ianera aqu9atia PIlera- 8utica SPECI o supua mE
Vaecinum arbDream Acei floridanum Teaxodum dstlchualL Quer'Zus yra Ace. flordacnnum
Callicarpa americar. Ulmas Catrpa emermcatia.
Fagus g-rancifola Fagus grandifoi.
Hicoria Qlaba. Hicoria glabra
Maqgolia. grandiflora. lagnola granditlova
Ostrya. vrginiaa Ostra vipginiarna
Prunu-s serotina Pranus secotnsa

Acer sacchinarin
ALnus pugosa.
Amorpha ftruiticoea
Betusa. nigas.
TRFLu-s deltoides


-- m S

.t .

- ---- -------~


Rock Outcrop.-Wherever the eroding side of a stream encounters;
resistant rock vertical cliffs or walls of stone follow as a matter of:
course. At the approximate level of the channel water the rock is.
necessarily wetter and therefore softer. These softer rocks near'
t'he stream yield to the carving forces of the water more readily
than do the higher and drier stones above. Consequently many:
stream cliffs show undercutting. This undercutting causes blocks
of stone to topple over and to go down, or to creep away from the
parent formation into isolated "chimneys" or columns. Naturally
enough such rocky bluffs have their distinctive species; liverworts
and certain mosses in the damper undercut roofs and walls, and:
other species of mosses and lichens on the drier exposed rocks or
cliffs. A number of ferns, flowering herbs, shrubs, and trees may
also be sought here. But the writer lacks details and can, therefore,
only generalize concerning habitats of this type.

Stable Slope.-Once the stream in its wanderings recedes from a
given side the slope begins to stabilize. The gradient tends to be-
come lower and soil accumulates. Plants come in, and associations,
succeeding one another over the years, will themselves enrich the
soil by decay, stabilize with binding roots, and ameliorate light and
water conditions by their very presence. In such a habitat we find
the climax forest trees of the particular geographic or climatic

To explain a climax forest or vegetation thoroughly, requires considerable
space. Suffice it to say that, as far as plant habitats go, there are two ex-
tremes: aquatic hydrophyticc) and dry xerophyticc). These two extremes
tend to become more moderate. Hydrophytic bodies of water gradually fill
up and become less hydrophytic, and dry exposed places tend to wear down
and gain more water. That is, both extremes in topographic features tend
to approach a common goal where water conditions are medium. Along with
these physiographic, water, and air conditions there come succeeding changes
in plant personnel. Hydrophytic aquatic species ultimately yield to those
requiring less water and xerophytic species give way to those requiring more
water and less light, so that ultimately a filled up pond or worn down rock
will be inhabitated or dominated by species peculiar to or requiring conditions
medium as to water, temperature, and light, and a mellow, well aerated soil
rich in minerals and humus. In northern Florida, beech and magnolia, or
beech, magnolia and Florida hard maple form the dominant climax forest
species with an occasional smooth hickory, black cherry or American ash.

Subordinate species of such a climax are the ironwood, a small
tree, and French mulberry, a shrub. There are, of course, typical


Sherbs and vines, too; and if. the association is disturbed, a great
number of other trees and shrubs may come in as impurities, espe-
cially in clearings. The spruce pine is often found in such areas.
It is interesting to note that on the stable portion of the slope in
cur river transect a number of interesting herbs, shrubs, and trees
are often associated with or near the climax forest species. The
'endemic Torreya, the leatherwood of the far north, and the
northern disjuncts referred to in the introduction are to be found in
these more or less stable slopes.
Here and there resistant stone has stood against the wear and tear
of the ages. These rocky outcrops, removed from the ravages of the
flood water and made moist, cool, and shady by seepage waters and
a forest canopy, produce plant habitats which are in striking contrast
to the exposed rock masses of the river front. The latter at times
may locally be extremely dry, hot, or cold and intensely lighted.
These protected rock or cliff relics of the climax forest slope offer a
congenial habitat for many species of liverworts, mosses, ferns, some
flowering herbs, hydrangeas and still others.
Oxbows,-Not uncommonly meandering streams cut new channels
across the neck of the loop. The abandoned loop may now become
an oxbow lake with more or less permanent water. Just how per-
manent or deep the water of such a lake is depends of course on a
number of other subsequent physiographic developments. In any
event these oxbows, too, have their peculiar species. Here thrive
tupelo gum, ogeche gum, bald cypress, red maple, plane tree, water
ash, Virginia willow and now and then a water honey locust. The
age of the oxbow, frequency of flooding, and permanence of water,
all enter in determining the species, but as yet we make no attempt
to correlate the species listed with particular stages, ages, or kinds
of oxbow lakes.
Flood-plain Propcr.-The writer uses this phrase for that part or
those parts of a flood-plain that can not be definitely called an ox-
bow, levee, spillway or run, or bar. The flood-plain proper really
comprises most of the river swamp. There we find all kinds of local
variations. Some areas are often flooded, and others seldom flooded.
Regions of erosion and regions of deposition occur alternately. In
_)ne place or level there may be clay or sand; in another, silt or
gravel. The flood-plain proper is therefore a locality of great in-
stability, making foothold or rooting difficult for some plants, and
making it hard for others to keep heads or tops above flood water.
SRelatively few perennial herbs can adapt themselves to such periodic


violence. On the other hand, the variety of sub-stratum conditions,
the abundance of water along with the new soils that floods bring
from time to time, favor a mixed forest luxuriant of growth and
abundant in arboreal and climbing species. Even though almost all
the species found in the levees, oxbows, or even river banks or bars,
may stray anywhere into the flood plains, hackberry, cork elm, water
beech, overcup oak, water hickory, walnut, and box-elder may be
considered typical. In places the flood-plain will be marked by
spillways or runs from the overflowing channel. At the recession
of the flood the water returns to the channel by those very runs.
The spillways, unstable and often loaded with sand, offer difficulties
for plant establishment, but species like sycamore, silver maple,
cottonwood, are often found in them.
Levee.-When a stream overflows, it deposits the greater part of its
load at or near the rim, building up in this way a natural levee which
parallels the channel at the rim. The buried buttresses of the trees
attest to this accumulation of sand and silt from over-flowing
The levee may be only a few feet higher than the flood-plain
proper; yet this slight elevation, together with the better drainage
afforded by the nearness of channel wall, creates a habitat which in
environmental factors approaches climax forest conditions. We dis-
cover here a reappearance of the dominant climax forest trees of the
stable slope beech, magnolia, Florida hard maple, ironwood,
white hickory, redbud, spruce pine, and holly might be mentioned.
Besides these climax trees, there are other species like buckthorn,
bitter-nut, hickory, slipper elm, catalpa, smooth sumac, all of which
might be considered typical of levees. Then, too, there are some
species on the levee that are also common to flood-plain proper.
The levee situation offers an interesting illustration of the impor-
tance of little niceties in determining plant distribution. This
habitat, only a few feet higher than the interior flood-plain, provides
conditions just suitable for climax forest trees. On the other hand
the violence of occasional flooding or other conditions of the levee
seem to preclude establishment of such concomitant species of these
climax trees as, for example, Torreya, and leatherwood. Along
with this perplexing nicety there is here an almost startling illustra-
tion of the important role physiography plays in determining the
species content or complex of plant associations.
River Bar.-On the concave side of the curve of the stream, be-
cause of the lower velocity, the running water deposits its load and


forms a bar of sand or mud. A bar represents new land or habitat
for plants. The pioneer species of trees encountered here are black
willow, cottonwood, silver maple, alder, sycamore, riverbirch and
lead plant. From time to time the river floods the bar and builds it
up higher and higher so that eventually it is characterized by a
relatively greater stability, with consequent less frequent inundation
and more of the species of interior flood-plain.

River Bank.-Very frequently a stream confines its meandering
course within its own flood-plain. In such case the convex side of
the curve may be considered a river bank. From a vegetational
point of view such a topographic feature is most catastrophic.
Practically all we ever see here are toppling trees and exposed roots.
Retrogression and destruction are the rule. The species or indivi-
duals present on such a river bank are those that persist in spite of,
not because of the conditions.


1. River systems are marked by many types of topographic fea-
tures. The latter in turn are responsible for a great variety of plant
habitats. The sum total of all these habitats rather than stream
migration accounts for the abundance of species and locally luxuriant
river vegetation.
2. The Apalachicola River area is notable for its variety of species,
endemic Torreya, Florida yew, and for its northern disjuncts.
3. This is the first attempt to show the influence of the topographic
features of the Apalachicola River on the character of its tree as-
sociations. In this connection it is important to note that the slightly
higher elevation, (really only a few feet) of the levee causes a re-
appearance of certain climax forest trees there.


Habitat Total no. of species No. of species in
in habitat only 1 habitat
Upland ..................... ............. 27 12
Slope .......----...... ......---- ........-- 43 13
Oxbow --------------.... ................ 12 2
Flood-plain .----.------ ....-..--------- 36 4
Levee .............. .......................... 29 3
River bank, bar .......-.........-.......---. 11 2



(not repeated in other habitats)

0. 0 o Q 0

Upland -...--..-------.............-- -- 15 10 5 5 3
Slope --..------------------ 20 2 14 14 1
Oxbow ... ------------------ I 8 6 2 4
Flood-plain -------------------.--- ----------_. I 7 5 1


UPLANDS (27 species)

Asimina angustifolia
Batodendron arboreum
Callicarpa americana
Cercis canadensis
Cornus florida
Diospyros virginiana
Hamamelis virginiana
Hicoria alba
Hicoria glabra
Liquidambar styraciflua
Nyssa sylvatica
Pinus echinata
Pinus palustris
Pinus taeda
Pyrus angustifolia
Quercus alba
Quercus catesbaci
Quercus cinerea
Quercus laurifolia
Quercus margaretta
Quercus marylandica
Quercus ruba
Quercus stellata
Quercus velutina
Rhus copallina
Viburnum rufidulum

Dog pawpaw
French mulberry
Witch hazel
White hickory
Smooth hickory
Sweet gum
Upland gum
Short leaf pine
Long leaf pine
Old field pine
Crab apple
White oak
Turkey oak
Upland willow oak
Laurel oak
Small post oak
Black jack oak
Red oak
Post oak
Black oak
Southern black haw

Zanthoxylum clava-herculis Prickly ash

SLOPE (43 species)
Acer carolinianum
Acer floridanum

Red maple
Florida hard maple


Aesculus pavia
Aralia spinosa
Arundinaria tecta
Asimina parviflora
Batodendron arboreum
Callicarpa americana
Carpinus caroliniana
Cercis canadensis
Cornus florida
Cornus stricta
Dirca palustris
Euonymus americana
Fagus grandifolia
Fraxinus caroliniana
Hatesia diptera
Hamamelis virginiana
Hicoria alba
Hicoria aquatic
Hicoria glabra
Hydrangea cinerea
Hydrangea quercifolia
Ilex opaca
Juniperus virginiana
Liriadendron tulipifera
Magnolia grandiflora
Magnolia pyramidata
Morus rubra
Nyssa sylvatica
Nyssa biflora
Osmanthus americana
Ostrya virginiana
Pinus glabra
Platanus occidentalis
Prunus caroliniana
Ptelea trifoliata
Quercus lyrata
Quercus alba
Quercus prinus
Quercus shumardii
Rapidophyllum hystrix
Sebastiana ligustrina
Tilia heterophylla
Torreya taxifolia
Viburnum rulidulum

Viburnum semitomentosum Haw

Red buckeye
Devil's club
French mulberry
Water beech
Flowering dogwood
Strawberry bush
Water ash
Silver bell
Witch hazel
White hickory
Water hickory
Smooth hickory
Oak-leaved hydrangea
American holly
Red cedar
Tulip poplar
Red mulberry
Upland gum
Water gum
Wild olive
Spruce pine
Cherry laurel
Overcup oak
White oak
Cow oak
Leopard oak
Needle palm
Sebastian bush
Southern black haw


OXBOW (21 species)
Acer carolinianum
Amorpha fruticosa
Catalpa catalpa
Cephalanthus occidentalis
Fraxinus caroliniana
Gleditsia aquatic
Nyssa ogeche
Nyssa aquatic
Platanus occidentalis
Populus deltoides
Quercus obtusa
Salix nigra
Taxodium distichum
FLOOD PLAIN (36 species)
Acer carolinianum
Acer negundo
Amorpha fruticosa
Betula nigra
Bumelia lycioides
Callicarpa americana
Carpinus caroliniana
Catalpa catalpa
Celtis mississippiensis
Diospyros virginiana
Fraxinus americana
Fraxinus caroliniana
Gleditsia aquatica
Halesia diptera
Hicoria aquatica
Ilex decidua
Ilex opaca
Juglans nigra
Juniperus virginiana
Liquidambar styraciflua
Liriodendron tulipifera
Morus rubra
Nyssa ogeche
Nyssa aquatic
Pinus glabra
Planera aquatic
Platanus occidentalis
Populus heterophylla
Quercus laurifolia
Quercus lyrata

Red maple
Indigo bush
Water ash
Water locust
Ogeechee plum
Tupelo gum
Water oak
Black willow
Bald cypress

Red maple
Box elder
Indigo bush
River birch
Buckthorn tree
French mulberry
Water beech
American ash
Water ash
Water locust
Silver bell
Water hickory
American holly
Black walnut
Red cedar
Sweet gum
Tulip poplar
Red mulberry
Tupelo gum
Spruce pine
Laurel oak
Overcup oak


Quercus nigra
Quercus obtusa
Quercus pagoda
Quercus prinus
Sabal minor
Sebastiana ligustrina
Taxodium distichum
Ulmus alata

LEVEE (29 species)
Acer floridanumn
Acer negundo
Callicarpa americana
Carpinus caroliniana
Catalpa catalpa
Cornus florida
Cornus strict
Fraxinus amcricana
Halesia carolina
Halesia diptera
Hicoria aquatic
Hicoria cordiformis
Hicoria glabra
Ilex opaca
Juglans nigra
Liquidamber styraciflua
Magnolia grandiflora
Ostrya virginiana
Pinus glabra
Pinus taeda
Planera aquatica
Ptclea trifoliata
Quercus lyrata
Quercus nigra
Quercus prinus
Rhus glabra
Sebastiana ligustrina
Taxodium distichum
Ulmus alata
Ulmus fuihva

RIVER BANK OR BAR (11 species)
Acer saccharinum
Alnus rugosa
Anorphy fruticosa
Betula nigra

Water oak
Water oak
Spanish oak
Cow oak
Blue stem palm
Sebastian bush
Bald cypress
Cork elm

Florida hard maple
Box elder
French mulberry
Water beech
Flowering dogwood
American ash
Silver bell
Silver bell
Water hickory
Smooth hickory
American holly
Black walnut
Sweet gum
Spruce pine
Old field pine
Plane tree
Overcup oak
Water oak
Cow oak
Smooth sumac
Sebastian bush
Bald cypress
Cork elm
Slippery elm

Silver maple
Indigo bush
River birch


Diospyros virginiana Persimmon
Liquidamber styraciflua Sweet gum
Platanus occidenalis Sycamore
Populus deltoides Cottonwood
Quercus rubra Red oak
Salix nigra Black willow
Taxodium distichum Bald cypress

Florida Southern College
In our day and age, in which Michelson measures the length of
the standard meter to within an error of less than one in two million,
it has become the vogue to think of scientific measurements and
computations as uncannily precise and accurate. It may be proper,
therefore, to call attention to, and make an analysis of, certain pre-
tended accuracies in mathematical computations with measured
quantities found in the various technical periodicals and text books.
In all the fields of science where mathematical computations are
made (physics, chemistry, biology, hydraulics, strength of ma-
terials, etc.), wrong notions of accuracy are prevalent to an un-
believable degree.
To keep this paper from being too technical, the discussion will be
based on a few very simple ideas, namely:
1. The nature of a physical measurement. All measurements are
only approximate. When we say that the length of a rod is
measured to be 3.6 inches we mean to say that its true length
lies somewhere between 3.55 inches and 3.65 inches. The error
in the measurement of 3.6 inches may therefore be as large as
.05 inch. This measurement is said to be accurate to the nearest
two significant figures. For simplicity we shall omit the con-
sideration of measurements in which the error may be even
2. The idea of number of significant figures. For example, each
of the following numbers represents a measurement correct to
the nearest three significant figures: 84200, .0346, .0000205,
.0200, 6.00.
3. The accuracy of a measurement is indicated, in the number
representing it, by the number of significant figures and not by
the number of decimal places. This is easily seen in the fol-
lowing illustrations: .000024 Km. = .024 m. = 2.4 cm. =
24 mm. = 24000 mikrons. Here each measurement is obvi-
ously correct only to the nearest two significant figures.


4. In computing with measured quantities the result is in general
never more accurate than the least accurate measured quantity
used in the computation. Let us give a simple illustration.
The area of a rectangular field, 2163.18 ft. by 1.27 ft., is com-
puted by multiplication to be 2747.2386 sq. ft. How accurate is
this? By considering the true nature of the measurements we
see that the correct area lies somewhere between the values
(2163.175) (1.265) = 2736.416 and
(2163.185) (1.275) = 2758.061
or, rounded off to the nearest three significant figures, some-
where between 2740 and 2760. We see from this that the origi-
nal product (representing the area) is not accurate to more
than three figures, which is the accuracy of the least accurate
factor, 1.27. The product is not even correct to the nearest
three significant figures.
This general principle is also true for divisions and other
more complicated computations. An extensive theory of errors
and percent errors gives more information, but it will not be
used in this paper.
Most frequently encountered is:
1. The error of carrying out results to an accuracy incompatible
with the accuracy of the data.
Illustrations from various sources follow. In a recent num-
ber of Industrial and Engineering Chemistry 1 we find the com-
.066395 X .00282 X 5963.7 = 1.1166
and the statement "this result checks [!] the figure 1.117 used
in the formula." Since the number .00282 is correct to only 3
significant figures, the computed result would be reliable to no
more than 3 figures, namely, 1.12. How can the author then
say that this checks the figure 1.117, to four figures?
In this same issue we find the computation
0.998 1.0074
Three figure data, yet results pretending to be accurate to five
figures! The result should have been given as 1.01, known to
the nearest 3 figures only.

'Vol. 10 (Jan. 15, 1938), p. t1.


In a famous text on thermodynamics we find
"Weight of Fuel Mixture required per minute
(42.44) (80)
19.95 Ib"
(0.83) (205)
Here a part of the data is correct to only 2 figures, the factor
0.83 representing the highly uncertain value of the mechanical
efficiency of the engine. Hence, the result should be given to
no more than 2 figures (20 lbs.)
In a text on mechanics for engineers we find the problem
"Find the work done in raising 100 tons of ore from
a mine shaft 1500 ft. deep, hoisting apparatus having
total efficiency of 45%." The answer is given as
666 666 667 ft. lbs. !
This is a classic! Such an accuracy in the computed result
would require the load of ore to be measured to the nearest one-
thousandth of a pound, and the depth of the mine shaft correct
to the nearest one-ten thousandth of an inch!
In the same text the kinetic energy of a rotating flywheel is
computed to five figures,
K.E.= Iw'-=2 (1000/32.2) (2)' (20.94)=27234 ft. lbs.,
even though the value of the acceleration of gravity (g=32.2)
is given to only three figures.
Similar errors are found throughout the textbooks in the
applied sciences of mechanics, strength of materials, hydraulics,
thermodynamics, etc. These simple errors are unbelievably
frequent. In fairness we must say that some authors are very
accurate, but the sad fact remains that only rarely does one find
a textbook in the applied sciences that does not contain such
silly mistakes.
Who is responsible for all of this? Who taught these writers
how to make such ridiculous computations? Evidence will now
be given showing that the college textbooks in the basic com-
putational sciences (physics, chemistry, and mathematics) en-
courage these practices and actually teach these in their il-
lustrative problems.
In a recent excellent textbook in physics, we find an illustra-
tive problem computing the pressure of a column of mercury
76 cm. high at 0 C to seven figures with data given to only two
and three figures:
P = 76 (13.6) (980) = 1012928 dynes/cm.'.


In a general chemistry text the author uses three-figure data
to obtain a result to six figures:
750 X 10 X 273
V z ------- ---- -- 9.19 liters
760 X (273+-20) lters
then 9.19 X 1.429 = 13.1325 g. oxygen.
In a college trigonometry text we find the problem:
"The Star Sirius is 5.26 X 10" miles distant. How long
will it take light to travel from the star to us at 186,000 mi. per
second ?"
The data are given to only 3 figures, yet the answer is given
to 5 figures: Ans. 3254.4 days.
So far we had only illustrations of carrying out computations to an
accuracy incompatible with the accuracy of the data.
Other types of pretended accuracies and undesirable practices are
now listed:
2. Problems are given with data appearing to be measured quanti-
ties, yet computations are made as if the data were exact.
Illustration from a mathematics text:
X = 32.2 (2.6)-2 =---- = 4.7634
(93.5 1-_
S= -.1 ---------- = 83.807

3. Answers pretend to be exact when they are not-can not be
Illustration. The volume of a silo with inside diameter
= 20 ft. height = 12 ft. (using 7r = 22/7) is
V = rR'h = 22/7 (10)2 (12) = 3771 3/7 cu. ft.
4. Many texts, when working with 4-place logarithm tables,
always keep 4 figures in the answers, and never mention the
fact that the fourth figure is usually considerably in error.
5. When approximate values are substituted for the various ir-
rational and transcendental quantities, they are not taken ac-
curately enough. That is, errors are introduced into the result
due to the insufficiently accurate values of the rounded-off
values of quantities like

r / 2, sin 400, log 1.05


6. Data are sometimes given to an improbable or even impossible
degree of accuracy.
7. Problems involving physical constants are often carried out too
far. This is frequently done in the kinematics and dynamics
problems of mechanics involving the value of acceleration of
gravity, g = 32.2. Similarly in problems involving densities,
specific gravities, or atomic weights.


Some texts are literally filled with them while others contain very
few. They really shouldn't contain any such errors. It must be
noted also that some texts have few if any illustrative numerical
computations. A check of eleven recently published texts in college
physics showed nine of them to contain such errors. A random
examination of twelve chemistry texts, that contained numerical
computations, showed that eight contained such errors. Out of
forty-two freshman mathematics texts, twenty-nine had such errors.
Examination of nineteen most recently published texts in high school
mathematics showed seventeen with such errors.
The implications are profound and strange. The errors involve
such simple and elementary ideas, that a well-instructed freshman
will not only immediately detect them, but not make them himself.
Yet these same errors are being made by college professors in the
physical sciences and mathematics, men with the degree of Doctor
of Philosophy, heads of departments, men listed among the Ameri-
can Men of Science. Think of the enormous amount of time being
wasted in making these uselessly accurate computations. Of more
serious consequence, consider the deception. To encourage or per-
mit students to believe that they have computed, for example, the
weight of a barrel of water to the nearest one-hundredth pound,
when the result is not even correct to the nearest pound, is, no doubt,
one of the greatest intellectual frauds in education today.

Traditionally, the subject has received very little systematic atten-
tion or instruction. It has possibly been considered too elementary.
It has been taken for granted that students can see and learn these
principles by themselves. Not enough attention has been given to
ihe approximate character of all measurements of length, time,.mass


and the approximate character of all computed results based on these
Certain recent texts deserve great praise for giving treatments on
approximate computations-but they don't go far enough. They
don't incorporate these ideas throughout the text; they don't give
enough practice.
1. Wherever possible, discuss accuracy of results. This is just as
important as the checking of results.
2. Do not give problems with exact data only (these are really
unnatural) but also give approximate data-data representing
actual measurements. Most problems are too idealistic. We
need some of these, of course, to illustrate general principles.
3. Insert more illustrative problems showing actual treatment of:
(a) computations with approximate data,
(b) rounding off results,
(c) deciding on the accuracy of results.
4. Insert problems asking the student to investigate the effects upon
the results of given errors in the data.
5. All teachers of basic sciences should make a serious study of
the theory of measurements' and computations with measured
6. Have the students find errors in the texts. Have them make
criticisms of the authors. Nothing helps more to create con-
fidence in the student than for him to be able to show that some
man of science has done something ridiculous.
7. Introduce and use the symbol (approximately equal to) in
contrast with the symbol = (equal to).
8. Devote some actual lesson time to the study of the theory oi
measurement, and computation with approximate quantities,
before extended computations are taken up in the course.
Time spent on this will not be lost, but, on the contrary, will pay
big dividends.
9. Whenever such errors are found in new textbooks make com-
plaint to both author and publisher.
Two excellent references are:
Scarborough, J. B., Numerical Mathematical Analysis. (Baltimore: The
Johns Hopkins Press, 1930).
Twelfth Yearbook of the National Council of Teachers of Math. (New
York: Bureau of Publications, Teachers College, Columbia University,

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