lss PROCEEDINGS OF THE AMERICAN ACADEMY. 



directly comparable. Evidently the name r. hyomandibularis must be 

 restricted in Spelerpes to tin - Bhorl trunk of the ventral part of the 

 Beventh, which is included between the region of its separation from the 

 eighth and that of the giving off of r. hyoideus. Though much shorter 

 than in the tadpole, it is made up of the same components, except that 

 it docs not embrace the general cutaneous. This constituent is repre- 

 sented exclusively by the communicating branch from IX. to VII. 

 Since in Spelerpes this r. communicant IX. ad VII. is not received by 

 the hvomandibular trunk of seveu, but by r. hyoideus after its separa- 

 tiou from the trunk (Fig. 2), it is probable* that no general cuta- 

 neous fibres are included in the hyomandibularis proper. This, however, 

 is not a fundamental difference, being merely a question of the earlier 

 or later accession of r. communicans to branches of the seventh. In 

 one point, only, is a greater importance to be noted: r. mandibulars 

 ext. in Spelerpes probably does not contain, as in the tadpole, a genera] 

 cutaneous component. 



The (ft) r. hyoideus after receiving r. communicans from IX.-fX, 

 curves latero-ventrad and is distributed to m. digastricus and m. mylo- 

 hyoideus posterior and to the skin ventral to them. The main branch 

 (VII. hoi.) is figured iu neutral tint, since the proportion of the two 

 components was not accurately ascertained. 



F. Glossopharyngeus and Vagus. 



1. Hoots. — The roots of this group, like those of the seventh and 

 eighth, show apparently a close correspondence to the condition in 

 NectuniB, though a careful comparison will be necessary to determine 

 this with certainty. The most cephalic and most dorsal rout is the 

 lateral-line component (PI. l, Figs. 1, 2, /A". 1+2 ); it resembles dorsal 

 VII. in appearance and position. In this case, however, the rout is 

 composed of two bundles. It is equivalent to Kingsbury's /A.'-' and 

 tn Strong's first root of IX.-f X. 



The second rool (IX. M ) emerges one section (20 ^ thick) caudad 

 and Blightly ventrad of the first root ; it is composed of < I ) the char- 

 acteristic line colorless fibres of the fasciculus-communis component and 

 (2) a ventral bundle, presumably motor. It corresponds to Kingsbury's 



/ X. ' and t'i Strong's BeCOnd root. 



The third rool (A. 1 ), the equivalent of Kingsbury's X.\ emerges 



• It i- cf course (?) thai tome fibre* from the r communicans take a 



centripetal course in the r. byoidetu and thus reach the hyomandibular trunk of 



VII 



