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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.

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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

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

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