XIII 



PHYLUM CHORDATA 



545 



Fii 



IK')!").— Skull of Tiger (Fdii liyris). 

 BUuiivillc.) 



(After 



111 the shitJl of the Caniivora vera (Figs. IIGG and HON) there 

 are prominent sagittal and lambdoidal crests. The temporal 

 fossa^ are very deep; the 

 orbits arc not separated 

 from them by bone. The 

 relative development of the 

 facial region varies in the 

 different groups ; in the 

 Bears and their allies, and 

 in the Dogs, it is elongated ; 

 in the Cats it is very short. 

 The zygoma is strong and 

 greatly arched outwards. 

 The glenoid cavity is in the 

 form of a transverse groove, 

 to the shape of which the 

 transversely elongated con- 

 dyle is adapted. In the Cats 

 tliere is a large, rounded 

 tympanic bulla (Fig. 11G7), 

 the cavity of which is 

 divided into two parts — an- 

 terior and posterior — by a 

 septum, the anterior con- 

 taining the auditory ossicles and the opening of the Eustachian 

 tube; the bony auditory meatus is short: the paroccipital is closely 

 applied to the posterior surface of the tympanic bulla. In the 



Dogs the septum of 

 the bulla is incom- 

 plete, the auditory 

 meatus short, and 

 the paroccipital pro- 

 cess not applied to 

 the bulla. In the 

 ■Bears and their allies 

 (Fig. 1169), the bulla 

 is usually less dilated, 

 and the septum is 

 absent or only re- 

 presented by a ridge, 

 while the bony audi- 

 tory meatus is elon- 

 gated. 



Fig. IIOT.-Section of the left auditory bulla of Tiger (Fttis ^ "^^ ^^^^,\^'^„.'''^ 



tUjris). a. aperture of communication between the two t\xQ Pinilipedia ( J Ig, 



chambers into which the cavity of the bulla Is divided; i froN ' K A i 



a.ui. external auditory meatus; b.oc. basioccipital ; PI. il/2:j IS DrOaQ aild 



periotic; s. septum between the two chambers; Sq. ,.r.nn/lQr1 to + Koi- nn»>T 



squamosal. (After Flower.) lOUnueQ, latnei COUl- 



