300 H. W. NORRIS 
canal in the jaw, and in C. japonicus, according to Osawa (’02), 
fuses with a branch of the mandibularis V. In Proteus, Necturus 
(Driiner ’01) and Siren (Driiner ’04, Wilder ’91) the alveolaris 
does not enter a canal in the jaw. In Necturus Norris and 
Buckley (711) find that the alveolaris, on reaching the lower jaw, 
divides into two branches, one of which runs far anteriorly 
and comes into close association with a branch of the ramus 
mandibularis V. 
From the facts above stated there may be deduced two charac- 
teristics of the ramus alveolaris in urodele amphibians: (1) a divi- 
sion into two (or more) branches, one of which enters a canal in 
the lower jaw; (2) fusion within this canal with a branch of the 
ramus mandibularis V. The peculiar condition in Proteus, 
Necturus and Siren may be explained as due to the imperfect 
development of the opercular bone, it being too rudimentary 
to form a canal. In consequence of not being confined in a 
limited space, the alveolar and mandibular branches do not fuse 
completely. It is evident that the smaller dorsal branch of the 
alveolaris in Siren is the one which corresponds to the branch 
entering the canal in the jaw in most Urodela. This condition in 
Proteus Necturus and Siren can hardly be regarded as primitive, 
but accords very well with the view of Boas cited by Driiner (’04, 
p. 361) ‘“‘dass Siren, Menobranchus und Proteus Larvenformen 
selen.”’ 
11. The ramus palatinus VIT 
This nerve runs anteriorly, at first along the lateral border of 
the parasphenoid bone (figs. 11, 10, pal.), and farther anteriorly, 
ventral to its lateral border. Along its course many small twigs 
are given off to the dorsal wall of the pharynx and mouth. Not 
far anteriorly from its origin the nerve gives off a lateral branch 
(pal.2) which runs for some distance parallel to the main nerve ~ 
(pal.1), along and in the dorso-medial border of the pterygoid 
_ muscle, but gradually shifting laterally, gives off small twigs to 
the dorso-lateral wall of the pharynx, and, as a very small nerve, 
reaches the lateral: border of the antorbital cartilage (figs. 9, 8), 
where it receives the anastomosing branch from the ophthalmicus 
