FISHES 



301 



Fig. 334. — Section of the Eye of the Eel. 



The superficial vitreous and both retinal capillary nets can be seen 

 filled with indian ink (»■). The cells of the retinal epithelium form a broad 

 layer. There is no choroid present, the epithelial layer lying directly on the 

 cartilaginous sclera (s) ( X 169) (I. C. Michaelson). 



Fig. 33o. — The Retina of the Eel. 



Injected with indian ink, mounted in glycerme. The superficial vitreous 

 vessels are in focus : these are arterial ( y. 37) (I. C. IMichaelson). 



to the general avascularity of the teleostean retina ; indeed, it is the 

 only known case in which the vertebrate retina is directly vascularized 

 except in the colnbrid snake Tarbophis and in Mammals. 



The ciliary zone is narrow and, without folds or processes, may be 

 said not to exist so that the choroid apjoears to i3ass directly into the 

 iris (Fig. 336)1; only in a few amphibious types such as Anahhps do a 

 few processes exist. This region, however, provides the supporting 

 and accommodative apparatus of the lens. Dorso-nasally the latter 



^ See footnote p. 267. 



