170 



BLIND VERTEBRATES AND THEIR EYES. 



without an intervening stage like that of cornutus, and the pigment layer has lost 

 its pigment, whereas in Amblyopsis it was retained. 



The reduction in size from the normal fish eye went hand in hand with the 







3 



! '' ' ii , df Eyt-s of all Si>ccifs of AmblyopMd.c and Typhlinimlgr, d c, g. h. and t drawn under same 

 i ('it t 'liit!i^;,rl i ccrttitlu^ (b) L Itiilogasler papiUtJerus, (c) Cluilogasttr agassizii, drawn 

 to scale; (rf) Retina of Cltologasler cornutus: (r) Kttina of Chuiagasltr fapillijerus; (/) Eye of Typhlo- 

 molgf under lower magnification than d~f\ (g) Eye of Typhlichthys subierrattcus ; (ft) Eye of Amblyopsis 

 spdaus; (i) Eye ot Troglichlhys rasa. 



simplification of the retina. There was at first chiefly a reduction in the number 

 ol many times duplicated parts. Even after the condition in Chologaster pa pill if - 

 cms was ivachnl the degeneration in the histological condition of the elements did 

 not keep pace with the reduction in number (vide the eye of cornutus'). The 



