THE MAMMOTH CAVE. 99 
place by a prolongation forward of the external 
membrane of the globe; fifth, the globe was in- 
vested by loose areolar tissue, which adhered to 
it very generally, and in some instances con- 
tained yellow fatty matter,—in one specimen it 
formed a round spot, visible through the skin, 
on each side of the head, which had all the 
appearance of a small eye,—its true nature was 
determined by the microscope only. It is not — 
improbable that the appearance just referred to 
may have misled Dr. Dekay, where he states 
that the eye exists of the usual size, but covered 
by the skin. 
“Tf the superficial membrane above noticed 
is denominated correctly the sclerotic, then the 
pigment-layer may be regarded as the repre- 
sentative of the choroid. The form as well as 
the position of the transparent nucleated cells 
within the choroid correspond, for the most 
part, with the retina. All of the parts just 
enumerated are such as are ordinarily devel- 
oped from and in connection with the enceph- 
alon, and are not in any way dependent upon 
the skin. But if the lenticular-shaped body is 
the true representative of the crystalline lens, 
it becomes difficult to account for its presence in 
Amblyopsis according to the generally-recog- 
