of the Eye of the Common Calamary (Sepia Loligo). 3 
sclerotica, which is cartilaginous. 7,2. A cartilaginous part, 
which may be compared in some respects to the cornea of the 
Vertebrata. It has a large opening in its centre, through which 
the lens projects. 4, 4. A thin membrane which lines the inner 
surface of the preceding part, and extends a little beyond the 
edge of the opening in it. This membrane, which is covered 
on its inner surface with a dark pigment, may be looked on as 
a kind of iris. It is reflected on the anterior surface of the 
structure which supports the lens, and is continuous with the 
outer lamina of the anterior segment of the latter. J, J, 7,1. A 
silvery-like membrane, which may be called the conjunctiva. 
m,m. Kirst layer of the retina. Opposite that part where the 
optic fibrils cover the back part of the eye, this layer of the 
retina is joined by the fibrils immediately on their entrance, 
but further forward the fibrils run a little way within the 
sclerotica before joining the retina, which produces the ap- 
pearance of another layer. m, ”. Second layer of the retina. 
0,0. Pigment situated betwixt the two layers of the retina. 
p- The lens. It is a sphere divided into two unequal seg- 
ments, an anterior smaller, and a posterior larger. Betwixt 
the two segments is interposed a thin transparent membrane q, 
which is continued from the first layer of the retina, and is 
joined by athin membrane r, which arises from the sclerotica. 
The lens, as in the Vertebrata, is composed of laminz and 
fibres. The outer laminz of the lens are continued into a 
plicated structure situated around its circumference, on 
either surface of the membrane which is interposed betwixt 
the segments of the lens. s,s. A transparent membrane,which 
may be called the hyaloid. It does not, however, completely 
inclose the aqueous fluid which represents the vitreous hu- 
mour. ¢. A cartilaginous pulley, through which play the sub- 
divisions of a tendon u, common to a membraneous muscle 
surrounding either eyeball. 
Figure 2. Shows the intercrossing of the optic fibrils after 
their origin from the optic ganglion. 
Figure 3. A section of the layers of the retina magnified. 
a. The optic fibrils joining 6. the first layer of the re- 
tina. c. The pigment interposed between the first and second 
layers. d. Second layer of the retina, composed of short fibres 
perpendicular to its surfaces. e. A pulpy nervous substance 
in which the fibres end on the inner surface. 
