Kincspury, Columella Auris and N. Facialis. 329 
ligament, the nerve is on the inner side of the M. depressor 
mandibuli, MECKEL’s cartilage and the os articulare successively. 
It is separated by connective tissue from the mucous membrane 
of the mouth which it gradually approaches, lying on the 
dorsal (mandibular) side of the depression’ between the hyoid 
and mandibular arches. At about the level of the caudal bor- 
der of the eye, it divides into two branches, one of which con- 
tinues forward on the inner side of the jaw, the other moves 
farther ventrad and mesad ; both, however, become compressed 
between the M. submaxillaris and the oral mucous membrane 
of the floor on the mouth between the hyoid (tongue) and the 
mandible. 
No communication occurs between this nerve and the Ra- 
mus mandibularis internus of the fifth. 
In the larvae of Spelerpes” and Desmognathus the relations 
of the four main branches of the seventh nerve are in general 
essentially as in Necturus. The Ramus jugularis, however, in- 
stead of curving around the dorsal border of the otic division 
of the depressor mandibuli as in Necturus, in Spelerpes passes 
through that division of the muscle, while in Desmognathus, it 
passes under the entzve muscle. In both Desmognathus and 
Spelerpes it contains a cutaneous— undoubtedly lateral line— 
component which was not found in Necturus. Asin Necturus the 
M. depressor mandibuli receives its innervation from fibers that 
accompany the Ramus communicans. The relation of both 
the R. jugularis and the R. communicans to the stilus colum- 
ellae has been spoken of in connection with that structure. 
l“The R. alveolaris VIL, composed wholly of communis fibers, follows 
the posterior border of the suspensorium to the angle of the jaw. Along this 
part of its course, the R. alveolaris lies mesially of the hyo-suspensorial liga- 
ment, and anteriorly of the deep pharyngeal evagination which represents the 
embryonic spiracular cleft.’’ ’02, CoGHILL, G. E. The Cranial Nerves of 
Amblystoma tigrinum. /Journ. Comp. Neurol., Vol. XII, p. 228. 
2 The branches and distribution of the facialis in the larval Spelerpes have 
been correctly given by Miss M. A, Bowers: The Peripheral Distribution of 
the Cranial Nerves of Spelerpes bilineatus. Proc. Am. Acad. Arts and Sct., 
Vol. XXXVI, 1900. 
