IV CONTENTS. 



Fishes — continued pagb 



The Amblyopsidae 70 



Relationships of the Amblyopsida; ........... 70 



Distribution of the Amblyopsida; . . . . . . . . . . .71 



Amblyopsis spelaus ............. 71 



Troglichthys rosce .............. 72 



Typhlichthys .............. 72 



Typhlichtkys subterraneus ............ 73 



Typhlichtliys osborni ............. 74 



Typhlichthys ■wyaudotte . . . . . . . . . . . -75 



Chologaster cor nut us ............. 75 



Clwlogaster papilliferus ............ 75 



Chologaster agassizii ............. 76 



The color of the Amblyopsidae 76 



General habits of Amblyopsis ............ 80 



Respiration ................ 81 



Feeding habits of Amblyopsis . . . . . . . . . . . .81 



Habits of Chologaster . 85 



Reactions to Light .............. 87 



Breeding habits of Amblyopsis ............. 92 



Rivalry of Males and Secondary Sexual Differences . 93 



The Egg and General Development of Amblyopsis ......... 94 



The Migration of the Anus 95 



The Tactile Organs 96 



The Ear of Amblyopsis .............. ico 



Does Amblyopsis " hear " ? 102 



The Brain of Amblyopsis 106 



Conclusions on the Amblyopsida 109 



The eyes of the Amblyopsidae 110 



Chologaster papilliferus . . . . . . . . . . . . .110 



Chologaster agassizii . . . . . . .116 



Chologaster cornutus 117 



Typhlichthys subterraneus 1 20 



Troglichthys rosce .126 



Amblyopsis spela?us . . . . . . . . . . . . . . 1 34 



Summary of the Eyes of the Amblyopsidae . .......... 145 



Development and Later History of the Eye of Amblyopsis ........ 147 



Growth of the Eye from Time of its Appearance 157 



History of the Lens 158 



History of the Scleral Cartilages 158 



History of the Optic Nerve 159 



History of the Development, Maturity, and Degeneration of the Eye ..... 160 

 Comparative Rate of Ontogenetic and Phylogenetic Degeneration of the parts of the Eye . 164 



The Future of the Eye 166 



Retardation and Cutting off of Late Stages of the Development of the Eye . . . .166 

 Causes of Retardation and Cessation in the Development of the Eye . . . . .167 



The Eyes of Amblyopsis and the law of Biogenesis 170 



Conclusion ................ 173 



General Summarial Account of the eyes of the Amblyopsidae 175 



Phvletic Degeneration of the eye of the Amblyopsidae . ....... 175 



Results of Phyletic Degeneration on the Different Parts of the Eyes of the Amblyopsidae . 177 



Ontogenetic Degeneration 180 



Plan and Process of Phyletic Degeneration in the Amblyopsidae ...... 180 



The Cuban Blind Fishes 183 



History of the Work 185 



Zoological position of Stygicola and Lucifuga ......... 187 



Primary and Secondary Sexual Characters . . .187 



Distribution of Stygicola and Lucifuga . . . . . . . . . .188 



