332 GEORGINA SWERT. 
behind (3) are a few irregularly arranged cells. Of these (1) 
appears to represent the outer layer of the iris; (2) this 
group of cells is evidently a degenerate lens; (3) is the 
remnant of the inner layer of the iris and the group of cells; 
(4) appears to represent some ganglion cells. Within the 
pigment ball lies the mass of retinal cells, showing very httle 
differentiation into layers, and completely filling the cavity 
of the eyeball, there being visible no vitreous humour or lens 
(other than perhaps the group cf cells mentioned above). 
The outermost layer of cells is very densely packed, the 
cells having deeply-staining nuclei being apparently the 
outer nuclear layer. Between this and the pigment layer, 
and generally embedded in the latter, is a clear, almost 
homogeneous layer, probably representing the degenerate 
layer of rods and cones. 
Within the outer nuclear layer the cells are much less 
closely packed, especially in the centre of the mass, but no 
clear division into the usual layers is present. 
Along the median antero-posterior line is an irregularly 
double line of much flattened cells, associated with a thin 
fibrous layer, possibly representing internal limiting, and 
hyaloid membranes with nerve-fibre layer—the vitreous 
cavity being lost. No definite nerve-fibres are visible. 
(b) Older Individual. 
In this specimen the eye does not vary to any remarkable 
extent from that of the younger forms. Its depth below the 
surface is greater than in (a), being ‘54 mm., though it 
appears relatively less deeply situated, owing to the greater 
depth to which the hair-roots extend. 
The conjunctival sac extends almost completely round the 
eyeball, being only absent at one spot on the postero-ventral 
aspect—no doubt representing the place of exit of the optic 
nerve. Its walls are much more fibrous than in (a). ‘The 
sac does not appear to open to the surface in one eye of this 
