Coe and Kunkel— California Limbless Lizard. 895 
Lens.—The lens, while perfectly continuous with the retina, is 
strikingly differentiated from it by the absence of pigment. It lies 
on the side of the eye toward the exterior, and while the retina 
becomes more heavily pigmented in the course of its development, 
in many respects the two exhibit some similarity in structure. 
The cells of the lens, in contrast with those of the retina, are less 
dense in nature, more homogeneous, and free from pigment. Strahl 
dnd Martin (’88) describe pigment in the lens of Anguwis, but this 
has not been substantiated by other investigators. Essentially, there 
is the same arrangement as in the rest of the eye, a layer of fairly 
tall columnar cells toward the cavity and a rather irregular layer of | 
shorter ones on the outside. Francotte describes in the lens two 
layers of fusiform cells, which probably correspond to the single 
layer which has been found here in Anniella. The cells are some- 
what more slender and longer than in the retina, and the nuclei 
apparently are more crowded and elongated and occupy more nearly 
the central portions of the cells, although frequently a nucleus is 
found pushed to one end or the other. External to the columnar 
cells is an incomplete layer of cuboidal cells, smaller than the corre- 
sponding ones in the retina and much more irregularly disposed, not 
forming apparently a continuous layer. These cells are not at all 
numerous and can be distinguished from the columnar ones only by 
the spherical nuclei, the cell outlines of all the cells being somewhat 
indistinct in these preparations. Béraneck’s (87) description of the 
histological structure of the eye in Anguis agrees with that of 
Anniella very closely. 
The lens is biconvex ; peripherally it has the same thickness as 
the retina surrounding it, and is in perfect continuity with the latter. 
The curvature of the two surfaces is usually different. The dorsal 
surface corresponds in curvature to that of the vesicle on the ventral 
side, so that ordinarily there is no bulging dorsally. Occasionally, 
however, there is a slight increase in the convexity of this part. On 
the ventral side, toward the cavity of the eye, there is considerable 
variation in the curvature, as may be seen in figs. 52-54. In one or 
two cases the convexity of the two sides of the lens was the same, 
but usually the inner surface was more strongly convex, forming a 
decided protuberance on the dorsal side of the cavity. The cell walls 
facing the cavity in general are delicate, so that the coagulum in 
contact with the cells has somewhat the appearance of streaming out 
from the cells. 
Projecting into the cavity of the eye from the fee ends of the 
columnar cells of the lens are numerous processes quite similar to 
