204 W. BALDWIN SPENOEE. 



It is thickest in the line of the optic axis^ and thins off to each 

 side, where it joins the retina. The lens is, in fact, doubly 

 convex, its anterior surface being in close contact with the 

 investing connective tissue, and parallel to the surface of the 

 dome-shaped cornea above. 



Retina. — The retina, owing to the compression of the eye, 

 may be likened in shape to the walls of an oblong box, the 

 lid of which is formed by the lens. The rods line the internal 

 surface, and are very clearly marked ; none appear to be espe- 

 cially elongated ; their external ends are in connection with a 

 layer of spherical-shaped elements {n}), as in other forms these 

 elements being also of the same size as the nuclei of the lens. 

 Most externally lie a layer of cone-shaped bodies (Co.), whose 

 inner ends taper off into processes passing to the spherical or 

 rod elements, whilst their broad bases lie upon the external 

 limiting membrane of the eye. 



Epiphysis. — The eye appears to be completely separated 

 off from the proximal part of the epiphysis, which consists of 

 (1) a proximal part with walls of distinctly nucleated cells, 

 which extends vertically from the thalamencephalon to the roof 

 of the brain cavity ; and (2) of a solid thin part running for- 

 ward along the brain roof from the proximal part towards, but 

 not reaching as far as, the parietal foramen ; it is enveloped 

 in pigment, and, being very thin, is somewhat difficult to 

 trace. 



Anguis fragilis, PI. XVII, fig. 25. 



This form has been described and figured in detail by de 

 Graaf,^ but in certain important points I am unable to agree 

 with him. 



Fig. 25 represents, somewhat diagrammatically, a longitu- 

 dinal vertical section through the foramen, the eye, and the 

 epiphysis. The eye in the specimen figured was considerably 

 smaller than the foramen, and the epiphysis was remarkable 

 for running forward until very close to the eye, whilst its distal 

 rounded extremity was invested by pigment cells (Ep. pig.). 



' Op. cit., pi. 4, fig. 34. 



