33 



PLATE I. 



Figures 1, 2, 4 and 5 were magnified 100 diameters, figure 3 

 was magnified 150 diameters, the entire plate was then reduced 

 to two-thirds in reproduction. 



Fig. 1. Longitudinal section of eye of 9 mm embryo. The sec- 

 tion is slightly posterior to the optic stalk, a part of which is shown 

 between pigment layer and portion of the diencephalon visible to 

 right. 



Fig. 2. Longitudinal section of eye of 20 mm. embryo. The 

 section shows plainly the connection between the vitreous body and 

 the extraocular mesenchyme, which is invading the optic cup 

 through the perilenticular opening; also extensive vascular system 

 and considerable differentiation of central portion of retina. 



Fig. 3. Longitudinal section of eye of 8 mm embryo. Lens 

 vesicle complete, choroid fissure wide open, mesenchyme pressing 

 into optic cup through choroid fissure. 



Fig. 4. Horizontal section of eye of 12 mm embryo. Hyaloid 

 artery has penetrated to lens vesicle. 



Fig. 5. Longitudinal section of eye of 25 mm embryo. Hya- 

 loid artery entering through optic stalk, has given rise to extensive 

 vascular system which penetrates larger part of vitreous body. 



