490 



THE RABBIT 



CHAP. 



the auditory aperture (aud. me) . The occipital segment 

 is completed above by the supraoccipital (s. oc), bounding 

 the foramen magnum above ; it has a pitted surface and 

 is marked externally by a shield-shaped prominence. 



The middle, or parietal segment, consists of five bones 

 Q. basisphenoid (b. sph) below, an alt sphenoid (a. sph, 

 as) on either side, and two parietals* (pa) above. The 

 broad posterior end of the basisphenoid is connected 



f 



nur.lb 



_\7 



p.aph 



paroc 



FIG. 133. Skull of Rabbit in longitudinal vertical section. (Nat. size.) The 



cartilaginous nasal septum is removed. 



a. sph. alisphenoid ; e. oc. exoccipital ; e. tb. ethmo-turbinal ; eth. ethmoid ; fl. fossa 

 for flocculus of brain ; '. incisors ; mx. tb. maxillary turbinal ; n. tli. nasr, 



turbinal ; pal', palatine portion of the bony palate ; p. sf>li. pnsphriioid ; s. I. 

 "n which the pituitary body lies ; I, region at which 

 the olfactory nerves leave the skull ; II, optic foramen ; V inn. foramen for 



sella turcica, or depression in which the pituitary be 



mandibular division of trigeminal ; VII, for facial nerve; VIII, for auditory 

 nerve; IX, X, XI, for glossopharyngeal, vagus, and spinal accessory; XII 

 for hypoglossal. Other letters as in Fig. 132. 



with the basioccipital by a thin plate of cartilage, and 

 tapers in front to a blunt point : it is perforated at about 

 its middle by an oval pituitary foramen, and on its upper 

 surface is hollowed out to form a depression in which 

 the pituitary body lies (s.t). The alisphenoids are 

 wing-like bones, directed upwards and outwards, and 

 firmly united with the basisphenoid : each is produced 

 vcntrally into a pterygoid process (as) , consisting of two 



