Landacre, Taste Buds of Ameiurus. 25 



From Table VI it will be seen that buds appear first on the 

 skin of the mandible (group B) in series L where there is one bud. 

 None are present in M and two in N. In series N buds appear 

 on the mental and post-mental barbules, but there are a few sec- 

 tions in O' and P lying between the buds on the mental barbules 

 and those of the lower lip devoid of buds. Notwithstanding 

 this slight discontinuity, there seems to be no doubt of the pro- 

 priety of including the barblet buds with the anterior mandibular 

 or lip group, since buds situated farther back on the lower jaw 

 do not appear until series U, when buds appear on the posterior 

 portions ol the operculum. Buds which would be most likely 

 to be confused with these in later stages are those of the 

 posterior mandibular divisions of the post-orbital and opercular 

 group, which do not appear until the 11 mm. embryo, so that the 

 group is quite homogeneous in distribution and time of appear- 

 ance compared with any other group with which it might be con- 

 fused. Functionally this group probably serves the same pur- 

 pose for the lower jaw that the buds of the nasal group do for the 

 dorso-lateral portion of the head. Buds of the lower jaw, for in- 

 stance, have extended as far back as section 30 in O', while those 

 of the nasal group have extended to the 38th section. 



It is not possible to make a comparison of the mental and post- 

 mental barbules with the maxillary and nasal on account of the 

 pliable character of the structures. 



The posterior limit of the anterior mandibular group moves 

 posteriorly slightly in the earlier series until it reaches a point 

 just back of the post-mental barblet, but in series U the pos- 

 terior buds of this group lie in section 53, so that there is prob- 

 ably up to this time little actual spreading. This must occur 

 in later series, however, since according to Herrick the buds 

 of this group supplied by the ramus mand. V occupy the whole 

 extent of the mandible. 



The innervation of buds on the lateral portion of the lip and 

 mandible is by the external branch of ramus mand. V, while 

 that of the mental and post-mental barblets is from the internal 

 branch of that nerve along with the middle of the lower lip, the 

 lower breathing valve and the mucosa of the mandible. 



It is of interest to note in this group, first, the slight discon- 

 tinuity in the appearance of mental and post-mental barbule 

 buds, since they represent the posterior extension of the lower 



