38 



GENERAL ANATOMICAL CHARACTERS 



inner and under surface is frequently dilated into a shell-like 

 auditory bulla (Fig. 8). The small bones of the internal ear known 

 as the malleus, incus, and stapes are contained in the membranous 



tympanic cavity, 

 which is situated in 

 a space left among 

 this group of bones. 

 Further mention of 

 these bones is made 

 below under the 

 head of the sense 



C2J- 



organs. 



In the Carni- 

 vora and some other 

 groups the foram- 

 ina on the base of 

 the skull for the 

 passage of blood- 

 vessels and nerves 

 are of considerable 

 taxonomic import- 

 ance. The position 

 of the more im- 

 portant of these 

 foramina is indi- 

 cated in Fig. 8 ; 

 but for details the 

 reader may refer to 

 the work on the 

 Osteology of theMam- 

 malia already men- 

 tioned. Attention 

 may, however, be 

 particularly di- 

 rected tO the SO- 

 sphenoid canal ; P, paroccipital process of exoccipital ; m, mastoid ,, , ,. , .-. 

 process of periotic ; am, external auditory meatus ; g, glenoid for- Called allspnenOlCl 

 amen, below which is the glenoid cavity for the condyle of the man- canal, the position 

 dible. (Flower, Proc. Zool. Soc, 1869, p. 25.) _£ -lylijf;^ jg shown 



in Fig. 8, since this is a feature of some importance in the classifica- 

 tion of the Carnivora. This canal is a short channel running hori- 

 zontally forward from near the foramen ovale through the alisphenoid, 

 and opening anteriorly with the foramen rotundum ; it is traversed 

 by the external carotid artery. 



Only in those species, as Man and the smaller kinds of the 

 Primates and some other orders, in which the brain holds a large 

 relative proportion to the rest of the body, does the external form 



Fig. 8.— The right half of the hinder part of the base of the 

 cranium of the Wolf (Canis lupus), c, Condyloid foramen ; I, fora- 

 men lacerum posticum ; car, carotid canal ; e, eustachian canal ; 

 o, foramen ovale ; a, posterior, and a', anterior aperture of ali 



