THE EYE OF CRYPTOBRANCHUS. 23 



eye, are frequently seen large, black, many-branched pigment 

 cells (A). 



The corneal epithelium (E) is a direct continuation of the gen- 

 eral epithelium of the head, there being no lids. As seen in the 

 figure, the corneal epithelium is somewhat thinner than that of 

 the rest of the head, and is composed of several layers of small 

 cells with strongly-staining nuclei ; the nuclei of the deepest 

 layer are somewhat larger than the more superficial ones. 



M 





Mo 



FIG. i. Section through the eye of Ciyptobranchus Alleghenitnsis. C, cornea; 

 Ch, choroid ; E, epithelium (conjunctiva) ; /', fold of the retina; G, ganglion-cell 

 layer of retina ; G7, gland in the skin near the eye; /, iris; Ig, ingrowth of choroid 

 into the cartilaginous sclerotic; L, lens; Lc, lens capsule; M, muscles; Mo, 

 molecular layer of retina; N, inner and outer nuclear layers of retina; Op, optic 

 nerve ; P, pupil ; Pg, pigmented layer of retina ; Ps, branched pigment cells ; R, 

 layer of rods and cones of the retina ; Sf, cartilaginous sclerotic. 



In spite of the fact that the eye seems to have practically no 

 power of motion, there are present the usual muscles, and they 

 are of considerable size ; two of them are shown in the figure (M). 



The choroid (Ch) lies in immediate contact with the inner sur- 

 face of the cartilaginous sclerotic, and is continued in between 

 the front of the lens and the back of the cornea, in the usual 



