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 

 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 the Mam- 

 malia already men- 

 tioned. Attention 



FIG. 8. The right half of the hinder part of the base of the r i 



cranium of the Wolf (Canis lupus), c, Condyloid foramen ; I, fora- mav > > -QOWCVer, D6 



men lacerum posticum ; car, carotid canal; e, eustachian canal; particularly dl- 



o, foramen ovale ; a, posterior, and a', anterior aperture of ali- rected to the SO- 

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



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



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



dible. (Flower, Proc. Zool. Soc., 1869, p. 25.) Qf which j g gh()wn 



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 



