EYES OF CHRYSOCHLORIS HOTTENTOTA AND C. ASIATICA. 329 
The conjunctival sac is lined by a stratified epithelium of 
two or three layers, similar to that covering the surface of the 
body (PI. 6, figs. 1 and 2, c.). 
The eyeball consists in general of the usual parts found in 
such degenerate eyes, representing the normal structures of 
an adult functional eye. 
In length, antero-posterior diameter, the eyeball is ‘51 mm., 
its transverse diameter being ‘42 mm. 
The fibrous sclerochoroid (Pl. 6, figs. 1 and 2, s.c.) is well 
developed, the front part of the choroid being somewhat less 
compact than the hinder. The retinal pigment layer (PI. 6, 
figs. 1 and 2, p.r.) is very well defined ; its epithelium of large 
cubical cells with slightly-staming nuclei almost completely 
surrounds the eyeball lying just within the sclerochoroid. Its 
pigmented area is considerably restricted being only present 
in the posterior one third of the eye, where, however, it has a 
considerable thickness. It extends somewhat further for- 
wards on the ventral wall of the eyeball (PI. 6, figs. 1 and 2). 
There is, however, a gap in the retinal pigment layer pos- 
teriorly, nearly in the median longitudinal line, this indicating 
the region of exit of the optic nerve (Pl. 6, fig. 2, g.). The 
bending in of the pigment epithelium to become continuous 
with the nervous layers of the retina is very well defined, 
taking place at about one fifth of the length of the eye from 
the anterior or cuter end. In front of this reflexion, a well- 
marked structure passes right across the eyeball, leaving an 
anterior chamber quite separated from the posterior chamber 
which latter is quite filled with the retina. This degenerate 
iris (Pl. 6, figs. 1 and 2,7 + /) arises from the inner layers 
of the sclerochoroid. It is thin around its origin, but swells 
out in the centre where it contains an irregular mass of cells 
in a fibrous-looking matrix ; this is evidently the degenerate 
lens. The rest of the iris consists of a more crowded layer 
of cells anteriorly, and an areolar layer in the middle. 
As the retinal pigment layer passes towards the median 
longitudinal line of the eye and almost at right angles to it, 
it becomes associated with a blood-vessel (PI. 6, fig. 2, b.v.) 
