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 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, 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.

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
CHAPTER VII
PAGE
Definition and Characters—Position of the Class Reptilia in the Phylum Vertebrata—Classification—Skull and Vertebrae [277]
CHAPTER VIII
Proreptilia—Prosauria—Theromorpha [285]
CHAPTER IX
Chelonia—Athecae—Thecophora [312]
CHAPTER X
Dinosauria—Crocodilia [412]
CHAPTER XI
Plesiosauria—Ichthyosauria—Pterosauria—Pythonomorpha [473]
CHAPTER XII
Sauria—Autosauri or Lacertilia—Lizards [491]
CHAPTER XIII
Sauria (continued)—Ophidia—Snakes [581]
INDEX [651]