Transcriber's note: Text enclosed by underscores is in italics (_italics_).
A single underscore introduces a subscript (CO_2), and a caret a
superscript (B^1).
Page numbers enclosed by curly braces (for example: {25}) have been
incorporated to facilitate the use of the Alphabetical Index and other page
references in the text.
* * * * *
THE
CAMBRIDGE NATURAL HISTORY
EDITED BY
S. F. HARMER, Sc.D., F.R.S., Fellow of King's College, Cambridge;
Superintendent of the University Museum of Zoology
AND
A. E. SHIPLEY, M.A., Fellow of Christ's College, Cambridge; University
Lecturer on the Morphology of Invertebrates
VOLUME VIII
[Illustration]
MACMILLAN AND CO., LIMITED
LONDON . BOMBAY . CALCUTTA
MELBOURNE
THE MACMILLAN COMPANY
NEW YORK . BOSTON . CHICAGO
ATLANTA . SAN FRANCISCO
THE MACMILLAN CO. OF CANADA, LTD.
TORONTO
_Frontispiece._ PHYSICAL FEATURES OF THE WORLD AFFECTING THE GEOGRAPHICAL
DISTRIBUTION OF AMPHIBIA AND REPTILES.
AMPHIBIA AND REPTILES
By HANS GADOW, M.A. (Cantab.), Ph.D. (Jena), F.R.S., Strickland Curator
and Lecturer on Advanced Morphology of Vertebrata in the University of
Cambridge.
MACMILLAN AND CO., LIMITED
ST. MARTIN'S STREET, LONDON
1909
_First Edition 1901_
_Reprinted 1909_
{v}PREFACE
Linnaeus had but a poor opinion of the Amphibia and their describers, or he
would not have called the former "pessima tetraque animalia," nor would he
have dismissed the latter with the terse remark: "Amphibiologi omnium
paucissimi sunt nullique veri." That was, however, nearly 150 years ago;
and at the present time there are fewer difficulties in writing a book on
Amphibia and Reptiles. Those who care for the study of Amphibia and
Reptiles–the Herpetologists, to give them their scientific title–have never
been numerous; but most of them have been serious students. One reason for
the fact that this branch of Natural History is not very popular, is a
prejudice against creatures some of which are clammy and cold to the touch,
and some of which may be poisonous. People who delight in keeping Newts or
Frogs, Tortoises or Snakes, are, as a rule, considered eccentric. But in
reality these cold-blooded creatures are of fascinating interest provided
they are studied properly. The structure of animals is intimately connected
with their life-habits; and this correlation is perhaps more apparent in
Amphibia and Reptiles than in any other class. The anatomist who studies
internal and external structure is as much struck with the almost endless
variety in details as he who takes the trouble to observe the living animal
in its native haunts, or at least under conditions not too unnatural. He
will agree with V. von Scheffel's Toad "that those above seem to have no
{vi}notion of the beauties of the swamp"–brilliantly coloured Newts engaged
in amorous play, concert-giving Frogs, and metamorphosing Tadpoles. The
motto assigned to the Reptiles seems singularly appropriate when we
consider that poisonous snakes have been developed from harmless forms, and
that many kinds of reptiles have lost limbs, teeth, and eyesight in the
process of evolution.
The present work is intended to appeal to two kinds of readers–to the
field-naturalist, who, while interested in life-histories, habits, and
geographical distribution, beauty or strangeness of forms, is indifferent
to the homologies of the metasternum or similar questions;–and to the
morphologist, who in his turn is liable to forget that his specimens were
once alive.
A great portion of the book is anatomical and systematic. It was necessary
to treat anatomy, especially that of the skeleton, somewhat fully, since it
has long been recognised that it is impossible to base a scientific
classification upon external characters. The reader familiar with
Vertebrate anatomy has a right to expect that questions of special
morphological interest will be dwelt upon at length. Those who have no
anatomical foundation must be referred to one of the now numerous
introductory manuals on the subject.
The account of the Amphibia is more complete than that of the Reptilia. It
was possible to diagnose practically all the recent genera; and this has
been especially done in the Anura, in order to show how in an otherwise
very homogeneous group almost any part of the body, internal or external,
can be modified in kaleidoscopic variety. The same could not be done with
the Reptilia. Their principal groups,–called sub-classes in the present
work, in order to emphasise their taxonomic importance in comparison with
the main groups of Birds and Mammals,–differ so much from each other that
it was decided to refrain {vii}from attempting a general account of them.
Moreover, the number of species of recent lizards and snakes is so
bewildering, the genera of many families being but tedious variations of
the same theme, that only those forms have been described which are the
most important, the most striking, or which the traveller is most likely to
come across. The student who wishes to go farther into systematic details
must consult the seven volumes of the _Catalogue of Reptiles in the British
Museum_ (London, 1889-1896). Mr. G. A. Boulenger, the author of this
magnificent series, has rendered the systematic treatment of recent
Amphibia and Reptiles an easy task. During many years of the most friendly
intercourse I have profited on countless occasions by his ever-ready
advice. Although he has kindly read the proofs of the part dealing with the
Amphibia it would be unfair to associate him with any of its shortcomings
or with contestable opinions, for which I alone am responsible.
Cope's large work on the Crocodilians, Lizards, and Snakes of North America
(_Rep. U.S. Nat. Mus. for 1898_ (1900)) has unfortunately appeared too late
to be used in the present work.
The drawings on wood were, with few exceptions, made by Miss M. E. Durham,
mostly from living specimens–a procedure which has to a great extent
determined the selection of the illustrations.
Since both the metric and the English systems of measurements have been
employed, it may be well to state for the convenience of the reader that
the length of a line of the text is four inches or approximately ten
centimeters.
I have frequently and freely quoted accounts of previous authors instead of
paraphrasing them. Especial thanks are due to Messrs. Longmans, Green, and
Co., and to Messrs. Murray, {viii}for their courteous permission to make
several long quotations from Sir J. E. Tennent's _Ceylon_, and from H. W.
Bates' _Naturalist on the River Amazons_.
Lastly, a remark about my Editors. Instead of being a source of annoyance
they have rendered me the greatest help.
H. GADOW.
CAMBRIDGE, _December 19, 1900_.
{ix}CONTENTS
PAGE
PREFACE v
SCHEME OF THE CLASSIFICATION ADOPTED IN THIS BOOK xi
PART I. AMPHIBIA
CHAPTER I
CHARACTERS AND DEFINITION—POSITION OF THE CLASS AMPHIBIA IN THE
PHYLUM VERTEBRATA—HISTORICAL ACCOUNT OF THE CLASSIFICATION OF
AMPHIBIA 3
CHAPTER II
SKELETON OF URODELA AND ANURA—SKIN—COLOUR-CHANGING MECHANISM—
POISON-GLANDS—SPINAL NERVES—RESPIRATORY ORGANS—SUPPRESSION
OF LUNGS—URINO-GENITAL ORGANS—FECUNDATION—NURSING HABITS—
DEVELOPMENT AND METAMORPHOSIS 11
CHAPTER III
NEOTENY—REGENERATION—TEMPERATURE—GEOGRAPHICAL DISTRIBUTION 63
CHAPTER IV
STEGOCEPHALI OR LABYRINTHODONTS—LISSAMPHIBIA—APODA 78
CHAPTER V
LISSAMPHIBIA (_CONTINUED_)—URODELA 94
CHAPTER VI
LISSAMPHIBIA (_CONTINUED_)—ANURA 138
PART II. REPTILIA {x}