No. 2.] EYES OF POLYCH^TOUS ANNELIDS. i8i 



As the eye is oblique, a transverse section (Fig. 35), near the 

 base, will show this condition of things. The mass of clear 

 cells on the left filling the pupil, or area between the edges of 

 the pigmented retinal cup, comes into contact with the lens and 

 forms a sort of raphe, ending at the stalk or connection of lens 

 and cuticle. This mass might be called an inner cornea, the 

 epidermis the outer cornea. The cuticle is removed from the 

 preparation figured. 



The central part of the lens, in sections, stains less deeply, 

 and is continued in the stalk as a tubular mass of coagulated 

 material opening to the exterior in some sections. 



The retina is much as in Nereis, but presents some difficulties 

 in connection with the fibrils passing to it from the lens. 



The pigment is dark red, yellowish red in separate spherules, 

 is present chiefly in the superficial parts of the cells, densely 

 aggregated at the zone next the rods, where there are clear 

 axial holes as in Nereis, and extends peripherally as irregular 

 processes or lines, much as in Nereis. 



The obvious arrangement of retinal nuclei in two zones (Fig. 

 34) is not due, I believe, to the presence of two fundamentally 

 different sorts of cells, but to the crowding of one sort, both 

 large and small, as represented in the portion of the retina 



(Fig. 38). 



In macerations (Fig. 45) both thick, and slender cells are 

 found, the former bearing clear, soft rods. These rods make a 

 definite layer, as in Nereis, between the pigmented cells and 

 the lens (Figs. 34, 35). 



The peculiar clear fibrils that come off from the macerated 

 lens are seen again in sections (Fig. 38) passing from the lens, 

 of which they are continuations, down between the rods to the 

 pigmented retinal cells. Again, in macerations, we find sharply 

 defined, clear linear bodies adhering to one side of the soft rod- 

 mass at the end of the thicker retinal cells (Fig. 45), on the 

 left. 



The actual connection of these lens fibrils with the retinal 

 cells is not satisfactorily made out, though sections (Fig. 38) 

 show pretty clearly that they are only the attenuated ends of the 

 more slender, reduced retinal cells, and not, as macerations 

 (Fig. 45) lead one to infer, parts of a superficial case about each 

 soft rod. 



