506 ANATOMY OF VERTEBRATES. 



The sella turcica is deep, and well defined 'by both the anterior 

 and posterior clinoids. The rhinencephalic fossa is relatively 

 larger than in most Carnivora, and is defined by a well-marked 

 angle of the inner table of the skull from the prosencephalic 

 compartment : the olfactory chamber extends backward both 

 above and below the rhinencephalic fossa : the upper part of the 

 chamber is divided into two sinuses on each side : the superior 

 turbinals extend into the anterior sinus, and below into the 

 presphenoidal sinus. The inner surface of the squamosal is tripar- 

 tite ; the upper facet rough for the broad squamous suture, the 

 anterior and inferior one smooth and deep for the natiform pro- 

 tuberance of the hemisphere, and the posterior facet smooth and 

 undulated where it is applied to the petrosal capsule, its juncture 

 with which is effected by the medium of the mastoid, which is 

 anchylosed to both. 



The strengthening of the cranium in Carnivora, in reference to 

 the forcible action of the muscles attached thereto, is gained by 

 the growth of bone in the form of ridges both from the outer and 

 the inner surfaces of the cavity. This is so completely filled by 

 the brain, its blood-vessels and membranes, that were any con- 

 cussion conceivable of cerebrum against cerebellum through an 

 active bound or leap, an interposed membrane so elastic as to yield 

 and recover would best meet the contingency : to suppose that a 

 hard plate between the two soft masses had any such relation to 

 the spring of the stealthy feline implies both dull physiological 

 reasoning and limited knowledge of the comparative osteology of 

 the Carnivora : the commonly ascribed final cause of the bony 

 tentorium of the Cat is refuted by the presence of that part in the 

 plantigrade Bears that do not move by bounds, and in the pin- 

 nigrade Seals that can only shuffle along the ground, and are 

 pillowed by the waves during their swiftest and most habitual 

 movements. 



The hyoid arch of Felines consists of stylo-cerato- and basi- 

 hyals, with the appended thyro-hyals. The stylo-hyals, as a rule, 

 connect the arch to the base of the skull : but in the Lion a long 

 ligament intervenes between the stylo- and cerato-hyals, allowing 

 more freedom of motion to the base of the tongue and larynx, in 

 relation to the characteristic vibratory roar of the king of beasts.* 



C. Bones of the Limhs. — The general characters of these in 

 the Carnivora have been defined, and the principal modifications 

 determining the pinni- planti-, and digiti-grade modes of loco- 

 motion are illustrated in figs. 172-175, pp. 288, 289. 



The pinnigrades are pentadactyle, and without trace of clavicle. 



' ccxxxvi , ol. vii. p. 38. 



