﻿176 



BLIND VERTEBRATES AND THEIR EYES. 



without an intervening stage lilce that of cormUus, 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 



mmm 



h 



Fig. 66. Diagrams of Eyes of all Species of Arablyopsid* and TyPMomolg,-. d c g h , and , drawn under same 

 magnification, (.a) Cko!og,2~l; corn^lm, (.b) Clwlogaster papMilcrus, (0 CWo.?..«^ "«a«.i". dra«a 

 to scale; (rf) Relma oi Cholo^aUer cornulus : (f) Relma of UuMgaMr papdhjcrus- (Q i-ye of lyPMo,- 

 molgc under lower magnification than d-/; («) Eye of TypUichthys subterrancus; (k) Eye of Amblyopsts 

 spdaus; {i) Eye ol Troglichtkys rosa. 



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

 of many times duplicated parts. Even after the condition in Chologaster papillif- 

 erus was reached the degeneration in the histological condition of the elements did 

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



