PIGMENT. 
205 
communicate or anastomose; in the majority of cases 
they certainly do not, but in the last named instance 
this point cannot be easily determined. The pigmen- 
tum nigrum from the eye of a Sheep, Fig. 152, a, 
FIG. 152 . 
A B 
a, pigmentum nigrum of the eye of a Sheep, b, pigmentum nigrum of the 
eye of an adult human subject. 
consists of cells of hexagonal 
figure, full of black granules ; 
if, however, the posterior part 
of the choroid he examined, 
as in the specimen, Fig. 153, 
it will be found that some of 
the cells are fusiform, whilst 
others are bifurcated at one 
or both extremities ; in the 
centre of each cell is a large 
white spot, which is the nucleus. 
In the pigmentum nigrum from the eye of an adult 
human subject (Fig. 152, b), the cells are much larger 
than those in the Sheep , and the granules also more 
FIG. 153 . 
Pigment-cells between the cho- 
roid and sclerotic coats of the eye 
of a Sheep. 
