THE CRANIAL NERVES OP SCYLLIUM. 119 



of the orbit the profundus is a superficial nerve, and, like the buccal, 

 is purely sensory in its distribution. 



On the other hand, it must be noticed that, as already pointed out, 

 the evidence is distinctly in favour of the distal portion of the profun- 

 dus (beyond the ciliary ganglion) being a branch of the third rather 

 than of the fifth nerve. Another point of distinction between them 

 lies in the fact that the former (the profundus) is distributed to what 

 is morphologically the dorsal surface, while the buccal supplies the 

 ventral surface. 



In the present paper we have purposely refrained from attempting 

 to determine the homologies between the nerves of Scyllium and those 

 of other vertebrates, preferring to wait until, by the study of the 

 development of other types, we are enabled to bring forward positive 

 evidence in support of our determinations. 



In conclusion we would express the hope that, by working out the 

 development of the roots and branches of the cranial nerves in a very 

 typical vertebrate, and following these roots and branches through 

 their subsequent changes up to their adult condition, we have rendered 

 more practicable than has hitherto been the case comparisons between 

 the descriptions of embryos and of the corresponding adult animals, and 

 have contributed something towards the establishment of comparative 

 neurology upon a firm and satisfactory basis. 



