156 ANATOMY OF THE RABBIT. 
cavity, the ridge indicating the position of the soft palate. Its 
lateral surface is partly applied to the maxilla and partly exposed 
to the orbit. Its dorsal margin is articulated with the presphenoid 
and with the ethmoidal process of orbitosphenoid, but a small 
posterior portion is free, so that the anterior portion of the basi- 
sphenoid is visible from the orbit. The free ventral margin forms 
posteriorly a thick projecting angle, the pyramidal process 
(processus pyramidalis), the base of which is cleft where it articulates 
with the medial and lateral laminae of the pterygoid process. 
Between the pyramidal process and the alveolus of the last cheek- 
tooth there is a conspicuous palatine notch (incisura palatina), 
connecting the orbit with the palatal surface. In the entire skull 
only the posterior portion of the lateral surface is visible from the 
orbit,-the anterior portion being concealed by the projecting bases 
of the posterior cheek-teeth. The ridge of bone on which the 
alveoli of these teeth are borne is separated from the palatine bone 
by the infraorbital groove. The medial wall of the latter, 
formed by the palatine bone, contains the orbital opening of the 
pterygopalatine canal and the sphenopalatine foramen. 
19. THE MANDIBLE. 
The mandible (mandibula), or lower jaw, comprises the two 
dentary bones (ossa dentalia), which, in che rabbit, as in mammals 
generally, are united by a fibrous or fibrocartilaginous connection 
(symphysis mandibulag); not coalesced, as in the human skull, to 
form a continuous siructure. As indicated above, each of the 
dentary bones comprises: (1) a horizontal, tooth-bearing portion 
which, in conjunction with that of the opposite side, forms the 
body of the mandible (corpus mandibulae); and (2) a posterior, 
vertical plate, the mandibular ramus (ramus mandibulae), for 
muscle attachment and articulation. The horizontal portion 
is deep posteriorly, where it lodges the alveoli of the cheek-teeth. 
Anteriorly, in the diastema separating the latter from the incisors, 
its dorsal surface is rounded and depressed, the space thus formed 
corresponding to a similar space in the upper jaw and serving 
chiefly for the accom.nodation of the lips, which in this region en- 
croach medially on the oral cavity. The medial surface of the 
ae 6 Petes res 
ks eae 
ee 
i a ee 
