54 Proceedings of Boyal Society of Edinburgh. [sess. 
taming numerous ganglion cells, thus constituting the ganglion of 
the facial proper. I did not, however, in the common root, distin- 
guish between the hyomandibular and facial proper divisions. 
( c .) Hyomandibular. — Runs downwards and slightly forwards, 
finally terminating in a very few ampullae and a peculiar gelatinous 
tissue under the skin over the first branchial cleft. Whether the 
practical absence of ampullae and the presence of this peculiar 
tissue point to the disappearance of the hyomandibular group of 
ampullae in connection with the disappearance of the spiracular 
cleft, is a question which must be left for future investigation to 
determine. The hyomandibular supplies the posterior of the hyo- 
mandibular canals (marked black in the figure — H) and sends a 
few twigs to the anterior. 
(cl.) External Mandibular. — This nerve is a branch of the hyo- 
mandibular (?) and runs downwards and forwards in front of the 
other branches of the hyomandibular to supply the greater part of 
the anterior division of the hyomandibular canal, and two groups 
of ampullte situated behind the lower jaw — one fairly large and 
the other very small, though perfectly distinct and innervated by 
a separate nerve. These ampullae are peculiar, being small and 
simple. Whilst, therefore, the outer buccal ampullae differ from 
the superficial ophthalmic in size only, the external mandibular 
ampullae differ from them not only in size but in structure 
also. 
(e.) Facial Projper. — Although there is no spiracle in Chimcera , 
this, the motor division of the Vllth, is well represented by two 
large nerves. Of these, one supplies the superficial muscles of and 
in front of the opercular fold, whilst the other, after giving off a 
largish branch which anastomoses with the chorda tympani, sup- 
plies the ventral portions of the same muscles, and also sends a 
deep branch to the muscles of the hyoid arch. These two nerves 
may correspond with the prae- and post-branchial divisions of the 
facial proper in the skate and shark. 
(f.) Palatine. — This large nerve, as already mentioned, springs 
from the fused hyomandibular and facial proper trunk just dista. 
to the hyomandibular ganglion, and has numerous ganglion cells at 
its base, which probably identify the ganglion of the facial proper. 
It runs forwards and dowirw ards, and is distributed mainly to the 
