FISHES 



319 



-T St' ~ f'-' £?«! 



Fig. 371. — The Tapetum of CJhondrosteans. 



The choroid of the sturgeon, Acipenser. The tapetum, T, lying between 

 the choriocapillaris, C, and the vessel layer of the choroid, V, pierced by 

 a large vessel from the latter to supply the former. The pigment epithelium, 

 P, is devoid of pigment apart from small accumulations on its inner surface 

 (a drawing after Miirr). 



(Fig. 371) ; in the ciliary region it becomes heavily j^igniented. The 

 sensory retina is characterized b}'- the large size of the horizontal cells, 

 the virtual absence of a distinct inner nuclear layer, and the small 

 number of ganglion cells which remain isolated without forming a 



Fig. 372. — The Angle of the Anterior Chamber of AciPE.xsEJi. 



A, argentea of iris ; AL, annular liganient ; C, cornea ; Ch, choroid ; 

 O, osseous placjues ; R, retina ; S. scleral cartilage ; V, vessel behind annular 

 ligament ; Z, zonule (from a drawing by Rochon-Duvigneaud, Les Yeux et la 

 Vision des Vertebres ; Masson et Cie). 



