328 TRAXSACTIOXS LIVERPOOL BTOT-OGICAT, SOCIKTY. 



aud ill each iiideiitatioii there is a delicate bundle of hair- 

 like " Stiftcheu " (fig. 47, St. s.), which appear to break 

 away from the cells in macerations. Thus the eye of 

 Buccinvm agrees with the long- series of eyes possessing 

 Stiftclien-bearing cells. TJie presence of such processes 

 is one of the most striking characters in the structure of 

 visual organs. 



There has been no small ditference of opinion as 

 to which are the visual cells in gastropod eyes. In 

 many cases the dilference between the cells which has 

 struck the observer has been the presence or absence of 

 pigment. Here both sets possess pigment. Could 

 the actual nerve connections be demonstrated, the 

 matter would be easily solved, but unfortunately the 

 fibrous processes of both cells merge into the tangled mass 

 of nerve fibres and connective tissue below the eye. 

 Judirine- from structures in the eye of Pecten, aud 

 especially from the character of the nucleus, the author 

 would say that the large cells are the visual cells not- 

 withstanding the fact that the cell body of the slender 

 cells is more in accordance with expectations. 



This view is, however, sup])orted further by two 

 facts. The large cells appear to j)ossess the " Stiftchen." 

 Both kinds of cells occur laterally almost up to the inner 

 cornea. There the large cells begin to disappear, whilst 

 the iiiK'lei of the others are very like, one might almost 

 say the same as, those found in the cells of the inner 

 cornea itself. According to this view, therefore, the 

 slender cells are merely suppoiiing cells, and the}- are 

 continued across the eye to form the inner cornea. 



The nuclei of the inner corneal cells are flat 

 compressed structures (fig. 47, Ps. cor.), like the nuclei 

 in tlie retina, but instead of ])eing arranged at right 

 angles io ihc u;ill oF Ihc ciiviU- Ihev iiiive rotated, so 



