298 H. W. NORRIS 
through the cranial wall the nerve trunk divides into a medial 
ramus palatinus and a lateral ramus alveolaris. This common 
origin of the two rami from the ganglion has been noted by 
Fischer (64) and Wilder (91). The following statement by 
Driiner (’04. p. 660) is, therefore, surprising: ‘‘Dadurch wie 
auch fiir den N. alveolaris eine besondere Austrittsoffnung weiter 
medial und ventral geschaffen, die wiederum von der des R. 
palatinus geschieden ist. Wir haben hier dadurch die Anfange 
der Bildung eines Fallopi’schen Canals mit 3 Austrittsdffnungen 
vor uns, eine fiir den R. palatinus, eine fiir den N. alveolaris und 
eine fiir die 4ussern Aeste.”’ 
On separating from the ramus palatinus the ramus alveolaris 
passes anteriorly, laterally and ventrally, at first between the 
pterygoid muscle and the quadrate cartilage (fig. 11), then be- 
tween the pterygoid and temporal muscles, then through the 
pterygoid muscle (fig. 10), emerging from the latter at the medial 
dorsal border of the lower jaw. It then passes along the inner 
border of the gonial bone, taking a position between the pterygoid 
muscle and the insertion of the tendon of the temporal muscle, 
just dorsal to the origin of the intermandibular muscle. Some 
distance anterior to the point where the intermandibular branch 
of the ramus mandibularis V passes through the lower jaw the 
alveolaris divides into a smaller dorsal and a larger ventral branch. 
The dorsal branch, passing around the anterior edge of the tendon 
of the temporal muscle, ascends to the dorsal medial border of 
the gonial bone and in close contact with it, giving off a few small 
branches to the mucous membrane at the lateral border of the 
pharynx. As the dorsal wing of the gonial gradually disappears 
the nerve comes to lie at the medial border of Meckel’s cartilage 
(fig. 8, alv.1). When the opercular bone (a thin scale-like tooth- 
bearing ossicle) is reached the nerve takes a position in a somewhat 
groove-like space between the opercular bone medially and Meck- 
el’s cartilage laterally (figs. 8-6), but the bone is never developed 
enough to enclose the nerve in a canal. As the nerve runs along 
the dorsal border of the operculare it is joined by a small branch 
of the mandibularis V (md.4a), which passes from the lateral bor- 
der of the jaw through the tendon of the masseter muscle to the 
