318 



THE EYE IN EVOLUTION 



Figs. 369 and 370. — The Chondrostean Eye. 



,ch 



s 



Fig. 369. — Diagram of a Chondrostean eye. 

 S Ch R 



ON 



Fig. 370.^ — Drawing of the eye of Acipenser ruthenus (Rochon-Duvigneaud, 

 Les Yeux et la Vision des Vertebres ; Masson et Cie). 



AL, annular hgament ; G, cornea ; Ch, choroid ; CP, cihary papilla ; 

 CT, connective tissue ; /, iris ; L, lens ; ON, optic nerve ; R, retina ; 

 S, scleral cartilage ; SL, suspensory ligament ; SO, scleral ossicles ; V, vortex 

 vein ; Z, zonule. 



The retina is primitive in its structure (Dogiel, 1883 ; Scliieffer- 

 decker. 1886). The pigmentary epithehum, resembling that of 

 Selachiajis, is practically devoid of pigment throughout the sensory 

 retina in -der that the mirror effect of the tapetum may be effective 



