368 PROCEEDINGS OF THE CANADIAN INSTITUTE. 
this muscle to the parasphenoid and that bone. Here it detaches a 
superficial branch for the mucous membrane over the entoptergyoid, 
and then penetrates the fleshy anterior part of the adductor arcus 
palatint where it forms two branches. The more medial of these is 
stronger and more superficial in the substance of the muscle, but 
both end in the premaxillary teeth and the mucous membrane of the 
lips and anterior part of the roof of the mouth. 
Ramus ad. m. adductorem mandibule.—This strong branch is 
derived from the supero-lateral strand immediately on its emergence 
from the skull, soon gains the dorsal aspect of the retractor muscle 
of the maxillary barblet which it supplies, and then distributes itself 
in the fleshy mass of the adductor mandibule after giving off a super- 
ficial branch. This (Fig. 3, Pl. IV.) contains fibres for the /evator 
arcus palatini and dilatator operculi, and also furnishes a cutaneous 
branch which communicates with a similar branch of the facial 
crossing the surface of the adductor mandibule. 
The mode in which the Rr. maxillaris and mandibularis are formed 
by the redistribution of the fibres of the supero-lateral and infero- 
medial strands is shown in Fig. 1, Pl. IV. Each nerve contains ele- 
ments from both strands. 
Ramus mawxillaris.—This branch is considerably smaller than the 
R. mandibularis, owing, no doubt, in part to the reduction and con- 
version of the superior maxillary bones. It is accompanied by the 
ramus buccalis as far as the hinder end of the palate bone where it 
divides into medial and lateral branches. The former turns over the 
dorsal surface of the palate bone, and ends in the lateral premaxillary 
teeth and the neighbouring skin, while the latter, after detaching 
some cutaneous branches, passes between the split tendon of the 
retractor muscle of the maxillary barblet and divides into two 
branches for the anterior and posterior aspects of the barblet. 
Ramus mandibularis.—The two constituent strands may remain 
separate while the nerve gains the dorsal aspect of the retractor 
muscle of the maxillary barblet. Here it gives off a branch which 
accompanies the tendon of that muscle to the posterior aspect of the 
barblet, and then divides into the external and internal branches. 
The former, A. externus is given off at the anterior border of the 
insertion of the adductor mandibule, and passes along the external 
edge of the lower lip communicating with a fine cutaneous branch 
of the facial which accompanies it at a somewhat lower level. The 
, io 
