CONTENTS. 



PAGE 



Preface vii 



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



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



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



A General Consideration of Caves and the Cave Fauna ......... 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 rathbuni . . . . . . . . . . . -31 



Sclera and Choroid .............. 32 



Pigment Layer Exclusive of the Irideal Parts . . . 33 



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



The Retina 35 



The eyes of Typhlotriton spelants Stejneger .......... 36 



Conclusions as to the eye of Typhlotriton spelaus 40 



Summary in regard to Typhlotriton . . . . . . . . . . . -41 



The Blind Reptiles 42 



Amphisbama punctata .............. 42 



Methods 42 



General Account of the Eye 42 



Minute Anatomy of the Eye ............ 43 



Rhineura floridana ................ 48 



Habits of Rhineura .............. 48 



General Account of the Eye of Rhineura .....*..... 49 



Minute Anatomy of the Eye of Rhineura .......... 50 



Typhlops lumbricalis ............... 54 



General Account of the Eyes of Snakes 54 



Eyes of Typhlops vermicularis ............ 55 



Eyes of Typhlops lumbricalis ............ 56 



Conclusions as to the eyes of Blind Reptiles .......... 59 



Awphisb&na ............... 59 



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



Typhlops .60 



Eyes of Cyclostome polistotrema stouti ............ 61 



Fishes .................. 62 



General Remarks on the Eyes of Fishes . . . 62 



The eyes of Zygonectes notatus . . 64 



Typhlogobius : The Point Loma Blind Fish and its Relatives . 65 



The Eyes of the Blind Catfish, Ameiurus nigrilabris 69 



iii 



