888 DKVRLOPMENT AND STRUCTURE OP PINEAL EYR IN LACERTILIA, 



Fig. 7a. — Hinulia sp., viewed as a solid object; shows the pineal eye 

 (In.) as a projection on the anterior surface of the cerebral vesicle. 

 The smaller projection Ep. is behind this. 

 [I have to thank Dr. Haswell for this figure drawn from a fresh embryo.] 



Fig. 8. — Section cf the head of Hinulia tivniolata, showing position of pineal 

 eye and epiphysis. 



Fig. 9. — Section of head of Hinulia ta'niolata, showing position of eye 

 relative to epiphysis. The eye is magnified in fig. 12. It also 

 shows the complex fonn that the epiphysis take. 



Fig. 10. — Vertical transvc-se section of portions of epiphysis (same stage as 

 fig. 9.) 



Figs. 11, 12, 13. — Section of eye in various stages showing the alteration 

 which it undergoes. All figures are drawn to same scale. 



Fig. 11. — Same as fig. 5. The eye is diflFerentiated off from the epiphysis, 

 but 18 not yet discontinuous with it. The skin is represented by 

 two superficial layers, the cuticle and the rete mucorum, while 

 below is the rudiment of the cutis vera. The lens of the eye is at 

 this stage concavo-convex in outline, while the optic vesicle is 

 double-convex. After this stage the shape of the optic vesicle is 

 altered througli the alteration in the outline of the lens. 



Fig. 12. — The eye has become more elongated and the lens is now double 

 convex, while the optic vesicle is concavo-convex ; the retina 

 remaining the same as before. Pigment is developed in the retina 

 in the lower ends of the rods and about the first spherical layer of 

 elements N". Also, in lowest layer N"" (fig. 6). The clear area is 

 now weU-defiued. The cuticular pigment is seen dipping down 

 below tha eye (Ot. Pig.). The front rudiment of scale is being 

 formed. Blood vessel runs below eye. The connective tissue is 

 collected into a suspensory band (Ct. B.). 



Fig. 13. — Eye still more elongated, the optic vesicle still smaller in doi'so- 

 ventral direction. Pigment has developed in the rods, and at the 

 place wliere the retina join.s the lens the pigment is developed 



