28 'Journal of Comparative Neurology and Psychology. 



head than the anterior buds ot this group in the later series owing to 

 the more rapid growth posteriorly of the lip and barblet group, but 

 this is not true at the time of the appearance of the nasal group. 

 While the nasal group lies dorsal to the maxillary group, it also rep- 

 resents the posterior spreading of the lip group since it lies farther 

 back on the longitudinal axis of the body at the time of its appear- 

 ance. Later, however, the nasal group probably represents func- 

 tionally the extension of the lip group to the dorsal portion of the 

 head. 



Subdivision C of this group is very peculiar in that it contains 

 but two buds up to series U. The position of these buds through- 

 out the earlier series is so nearly constant and their separation from 

 each other remains so nearly the same that there can be little doubt 

 that they are the same buds in all series. The constancy of these 

 two buds throughout so many series is still more striking when we 

 consider the fact the area between the nasal barblets and the mid- 

 dorsal portion of the eye of the adult is innervated according to 

 Workman ('oo) by communis fibers running out through four well 

 defined divisions of the ramus oph. sup. V and by several small 

 twigs. Comparing group C with group A, we find practically the 

 same stationary condition in that group, so that we shall have to 

 consider the areas on which these buds are situated as growing 

 slowly or else the spreading of the buds is practically wanting and 

 does not correspond closely with the number of nerve twigs supply- 

 ingthese two subdivisions. The gustatory fibers evidently do not run 

 to the surface simultaneously through nerve twigs which inner- 

 vate practically the same area. 



The whole group is characterized during the earlier stages of 

 Ameiurus by its practically stationary condition. The back- 

 ward movement in all the series except U can be accounted for 

 mainly by the growth of the embryo. 



Group C, while stationary in the earlier series, in the ii mm. 

 embryo spreads back as far as the middle of the dorsal portion of 

 the eye and it was puzzling to know whether to include some of 

 these buds lying over the eye in the nasal group or in a division 

 of the post-orbital group lying behind and above the eye and 

 innervated by the ramus max. acces. However, that group 

 appears along with the remainder of the post-orbital and opercu- 

 lar group; and, while the posterior extension of the nasal group 

 comes close to the anterior buds of the post-orbital group, still 



