LEIGH HOADLEY. 



The chambers in this case are well developed. A definite 

 anterior and posterior chamber are present separated by the lens, 

 the lenticular zone, and a thin layer of mesenchymatous tissue 

 which is covered with an endothelium. The entire anterior 

 chamber is lined by this tissue. The posterior chamber is large 

 and is lined throughout by the retina save at the anterior border, 

 where the lens and ciliary processes occur, as mentioned above. 

 It is not regular, however, for at intervals, as can be seen (Fig. 2), 

 the retina has proliferated to such an extent that there are folds 

 entering the cavity. In no place do these obliterate the chamber 

 as in some of the grafts. 



The retina and the tapetum are well formed, though where con- 

 volutions of the retina occur, the tapetum does not always follow. 

 On close examination, the tapetum appears to be formed of three 

 or four layers of heavily pigmented cells arranged very closely. 

 All of the layers of the retina are present (Fig. 3) but the layer of 



Mesen 

 Memb.ejt.tv.m 

 St Op. 



In Nuc 

 Out.Mol 

 . Nuc. 



FIG. 3. Cross section of retina from same graft as Fig. 2. (X 180.) B.C., 

 blood corpuscles. B.V., blood vessels. Cart., cartilage. Gaiig.L., ganglionic 

 layer. In.Mol., inner molecular layer. In.Xuc., inner nuclear layer. Memb. 

 Ext. Lint., external membrana limitans. Mesen., mesenchyme. Ont.Mol., outer 

 molecular layer. Out. Nuc., outer nuclear layer. St.Op., stratum opticum. Otlu-r 

 abbreviations as in Fig. 2. 



rods and cones shows but little differentiation, a condition cor- 

 responding to that found in normal eyes of chicks of the same age. 

 Bordering the cavity is the very thin membrana limitans interna. 

 This separates the cavity of the eye from the stratum opticum 

 which lies just beneath it. This is clear an<l ea-ily distinguished 

 from the sparsely nucleated outer ganglionic layer. Bet \\een ihi- 



