THE EYES OF AMBLYOPSIS. 



139 



It breaks up into smaller vessels distributed in the choroid. A vessel is usually found 

 in a groove of the pigment layer of the retina. This groove extends along the dorsal 

 wall of the eye — otherwise it might be taken for the choroid fissure (fig. 50, cps.). 

 A somewhat larger vessel than at other points is found near the iris, where this 

 structure appears to be continuous with a deep choroidal groove (fig. 51a, cps.). In 

 the young a blood-vessel enters the hyaloid cavity at this point. 



chr. 



sci c. 



3-7- 



9-- 



nil. 



The eye itself, exclusive of choroid 

 and sclera, differs greatly both in size and 

 inner structure although the general ar- 

 rangement of the retinal cells remains the 

 same in all cases. In some cases the pig- 

 ment layer of the retina forms a large mem- 

 branous bag many times too large for the 

 inclosed structures which lie as a small 

 ball in this comparatively vast cavity. In 

 such eyes found in old individuals the 

 wall in many places is free from pigment. 

 In general the pigmentation of the retina 

 fig. si. From Ambiyofists ?s mm. long killed in picric varies inversely as the pigmentation of 



Acid and stained with a Mixture of Ha?malum and . . . . T -. ...... . . 



Indigo Carmine. Figures made with Bausch and Lomb the CnOrOlQ. in Other individuals the eye 

 r ! a Immersion and 4 Eyepiece, 



(a) Section of Right Eye. Choroidal Groove with one of fomiS aCOmpaCt maSS Of Cells (fig. KT.). 



Scleral Cartilages in front of Eye. Nuclear Layers x \ o ^^»/ 



^^Af^Zg^JtT*^ T ° anticipate somewhat, the vitreous 



w j&tfattart. s. «■ showing Group of Elongate cavity with the hyaloid membrane and 



Uveal Cells ' its blood-vessels have entirely disappeared, 



the ganglionic cells have in large part been brought together into a solid mass, 



and the irideal opening has usually become closed. 



Pigmented Layer and Cones. — The pigment cells as they appear in the best 

 preparations of the better-developed eyes may be described first (fig. 50). The 

 cells are longest near the entrance of the optic nerve. They possess an outer seg- 

 ment, not determinable in all cells, which is free from pigment. They have a homo- 



