﻿CONTENTS. 



PAGE 



Preface . vii 



Introductory ................ vii 



Acknowledgments ............... viii 



Conclusions of General Import ............. ix 



A General Consideration of Caves and the Cave Kauna I 



Caves and the Cave Fauna .............. 3 



Caves in their Relation to the Rest of the Universe ......... 3 



The Nature of the Cave Environment ........... 5 



The Blind Vertebrates and Cave Vertebrates of North America ....... 9 



The Origin and Dispersal of Cave Animals . .......... 12 



The Origin of the Food Supply of Caves ........... 17 



Age of Caves in their Relation to the Variety of Cave Fauna 17 



Divergence in Epigean and Convergence in Subterranean Fishes 18 



Conclusions ................ 21 



Blind and Cave Vertebrates and their Eyes 23 



Mammals .................. 25 



Eyes of the Common Mole ............. 25 



The Cave Rat and its Eyes ............. 26 



The Cave Salamanders ............... 28 



The eyes of Typhlomolge rathbutii . -31 



Sclera and Choroid . 32 



Pigment Layer E.vclusive of the Irideal Parts ......... 33 



Iris and Ora Serrata .............. 33 



The Retina 3c 



The eyes of Typhlotriton spelceus Stejneger 36 



Conclusions as to the eye of Typhlotriton speUeus 40 



Summary in regard to Typhlotriton 41 



The Blind Reptiles 42 



Aviphisbana punctata .............. 42 



Methods ................ 42 



General Account of the Eye 42 



Minute Anatomy of the Eye 43 



Rhineura floridaua . 48 



Habits oi Rhineura .............. 48 



General Account of the Eye of /W/wtV/z-rf .......... 49 



Minute Anatomy of the Eye of y?^/«4'«/-a 50 



Typhlops lunibricalis ............... c a 



General Account of the Eyes of Snakes 54 



Eyes of Typhlops 7'erinicularis 55 



Eyes of Typhlops lunibricalis . 56 



Conclusions as to the eyes of Blind Reptiles 59 



Amphisbcena ............... eg 



Rhineura ................ 59 



Typhlops 60 



Eyes of Cyclostome polistotrenia stout i 61 



Fishes 62 



General Remarks on the Eyes of Fishes 62 



The eyes ai Zygonectes notatus ............. 64 



Typhlogobius : The Point Loma Blind Fish and its Relatives 65 



The Eyes of the Blind Catfish, Ameiurus nigrilabris 69 



iii 



