60 BULLETIN OF THE 
section, while the measurements in the case of the first three were made 
with the eyes in place in the head, the head having been cleared in 
clove oil. It is undoubtedly true, that some of the difference in size 
between the last mentioned eye and the first three was due to shrinkage 
in it during its passage through the paraffine. I have made numerous 
measurements of the same eyes before embedding and after cutting, and 
have always found the sections somewhat less in diameter than the 
whole eyes, even when all precautions had been taken to prevent shrink- 
age. But certainly shrinkage cannot account for the great difference 
found here between the eye measured in section, and the one of an in- 
dividual of the same length measured in the head. This small eye, I 
should add, was the only one that I have found in which the lens was 
wholly absent. This eye will be described later on. In a specimen 
25 mm. long the axial diameter of the eye was 0.28 mm., and its equa- 
torial diameter was 0.45 mm. Ina specimen 19 mm. long the diameter 
in the long axis of the head was 0.28 mm., and transverse to this it was 
0.39mm. It appears from these measurements that the eye does in- 
crease somewhat with the increase in size of the animal, though it is 
true that, in view of the obvious individual variation in size in specimens 
of nearly the same length, not enough of the smaller specimens have 
been studied to determine definitely how much this increase amounts to. 
A sclerotic coat, well defined from the surrounding connective tissue, 
is always present, though in some places its fibres, both singly and in 
bundles, leave their concentric course and pass off into the connective 
tissue, and thus bring about an intimate connection between the two. 
In some places the connective-tissue fibres not belonging to the sclera, 
but in its vicinity, are seen to have taken on a concentric direction even 
at a considerable distance from the eye, and to have become more 
numerous and more closely packed than is the case with the subcuta- 
neous connective tissue in general. There is thus brought about a 
fusion to some extent of the eye bulb with the tissue in which it is 
embedded. This statement applies especially to the eye the section of 
which is shown in Figure 6. In most sections numerous flattened con- 
nective-tissue cells are found in the sclera; and in all the eyes that I 
have sectioned the sclera is cartilaginous in the region corresponding to 
the ora serrata of the retina. The cartilaginous layer is usually only 
one cell thick, but occasionally it is two or more cells thick (Figs. 5, 6, 
and 12). In many specimens the cartilage does not extend entirely 
around the eye in the equatorial zone, and in no case have I seen it 
extend more than half-way back to the entrance of the optic nerve. No 
