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 ' Typlilomolge rathbuiu . . . .31 



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



Pigment Layer Exclusive of the Irideal Parts ......... 33 



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



The Retina 35 



The eyes of TypUotriton spcheits Stejneger .......... 36 



Conclusions as to the eye of Typlilotriton spelaus ......... 40 



Summary in regard to TypUotriton . . . . . . . . . . . .41 



The Blind Reptiles 42 



Amphisbtzna puiictata .............. 42 



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



General Account of the Eye ............ 42 



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



Rlrinenra floridana ............... 48 



Habits of Rliiiieiirij .............. 48 



General Account of the Eye of Rhiiieitra .......... 49 



Minute Anatomy of the Eye of ' Rhineiira .......... 50 



Typhlops liimbricalis ............... 54 



General Account of the Eyes of Snakes .......... 54 



Eyes of Typhlops vermicidaris ............ 55 



Eyes of Typhlops himbriialis ............ 56 



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



Amphisb/zna ............... 59 



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



Typhlops ................ 60 



Eyes of Cyclostome polistotrema stoitti . . . . . . . . . . . .61 



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



General Remarks on the Eyes of Fishes ........... 62 



The eyes of Zygonectfs notatus ............. 64 



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



The Eyes of the Blind Catfish, Anieiurus nigrilabris ......... 69 



iii 



