274 H. W. NORRIS 
bone, passes out almost directly ventrally between the dentary and 
the gonial! bones, and then divides anteriorly and posteriorly, 
its posterior division innervating the posterior portion of musculus 
intermandibularis posterior, the anterior part of m. interhyoideus, 
and the overlying skin, its anterior division supplying the ante- 
rior part of m. intermandibularis posterior, and all of m. inter- 
mandibularis anterior. It should be said, however, that an 
anterior intermandibular muscle is not sharply distinguishable. 
(b) A second branch or group of branches (md.3) of general cuta- 
neous fibers, the ramulus labialis, supplies the skin overlying the 
jaw for some distance anterior and posterior to the level of its 
origin from the main nerve. (¢c) The main nerve (md.4), ramulus 
mandibularis externus, passing along the dorso-lateral border of 
the dentary, gives off numerous branches, some of which, arising 
not far anterior to rm. labialis, are of considerable size, supplying 
the skin latero-ventral to the jaw and extending far anteriorly, 
and also reaching antero-dorsally as far as the upper lip. In 
some of these dorsal branches are doubtless included portions of 
ramuli labiales of other Urodela. Two of these posterior branches 
of the mandibularis externus (md.4a, md.4b) require more definite 
description. One of them (md.4a) arises on the dorsal side of 
the mandibularis externus, ascends through the anterior part of 
the masseter muscle (figs. 8, 9), and divides into two parts, the 
smaller dorsal division of which passes through the tendon of 
the median portion of the muscle and is then joined by a small 
nerve arising from the ventral (md.4b) of the two branches from 
the mandibularis externus. The combined nerves pass poste- 
riorly along the extreme lateral wall of the mouth just beneath 
the epithelium. The fibers either pass but a short distance or 
else’ soon lose their myelinic sheaths. The second division of the 
dorsal branch (md.4a) also enters the tendon of the masseter mus- 
cle, but farther anteriorly and close to the jaw. It passes medially 
through the tendon, over the jaw, and ventrally to join a branch 
(alv. 1) of the ramus alveolaris VII (figs. 8-5). Its subse- 
1 Gaupp (’11 b and ec) has proposed the name ‘goniale’ for the bone which quite 
generally in the urodelous Amphibia has been designated ‘angulare,’ pointing 
out the fact that the latter is an entirely different structure. 
