424 GRACE A. WELLS 



trally so as to form a basal angle ib.a., Gegenbaur's 'basalecke'). 

 On the lateral margins of this area there are somewhat crescent 

 shaped elevations which enlarge the articular surface. Antero- 

 lateral to this orbital region is the preorbital process (p. a.) and 

 postero-lateral to it, the postorbital process (p.o.), the concavity 

 of the orbit lying between these processes. 



In the otic region the ventral surface of the cranium is broad 

 and flat (the basal plate), with a slight median ridge extending 

 the length of the region. The ridge over the horizontal semi- 

 circular canal (h.c.) is seen just lateral to this flat plate, and 

 posterior to it the fenestra postotica (f.p.o.), as described in 

 connection with the dorsal surface, except that the notch in the 

 cranium (region of the ninth nerve) does not show in this view. 

 In the extreme posterior part of the median line there is a cres- 

 cent shaped depression for articulation with the first vertebra, 

 the triangular occipital condyles (o.c.) occurring on either side. 



Only a few foramina are seen on the ventral surface. Among 

 these are that for the main trunk of the ophthalmicus super- 

 ficialis (o.s.VII) and the row extending posteriorly for twigs of 

 the same branch, occur on either side of the narrow interorbital 

 region, passing through the base of the supraorbital crest. Me- 

 dial to these on either side and anterior to the palato-basal 

 articular surface is the optic foramen (o.IL). Posterior to the 

 articular surface in the median line is the foramen for the en- 

 trance of the united internal carotid arteries (int.c.) into the 

 cranium. Lateral and posterior to this median opening there 

 occurs a smaller foramen for the hyoid branch of the facial nerve 

 (f.VII). The foramen of the vagus (X) nerve is just visible at 

 the posterior margin of the cranium, between the occipital con- 

 dyles and the fenestra postotica. The foramen for the glosso- 

 pharyngeal nerve can not be seen in a ventral view. 



The only notable regions of muscle attachment on the ventral 

 surface of the cranium are those of the levatores labialis supe- 

 rioris which have their origin on either side of the median line, 

 just anterior to the palato-basal articular surface (L.ls.). At the 

 extreme posterior end, just in front of the foramen magnum, is 



