

MOUTH OF MAMMALS. 393 



nation the regurgitated bolus is driven into the mouth with 

 great force ; and the use of these papillae as mechanical obsta- 

 cles to its escape, and their tendency to confine the soft slimy 

 comminuted vegetable substances to the molar region during the 

 second mastication, appear to be offices of sufficient importance to 

 found upon their presence an argument of adaptation. Neither 

 the Hog nor the Horse have such buccal papilla? ; but the front 

 part of the mouth is closed by teeth both above and below, and 

 the food is not regurgitated for the purpose of undergoing a 

 lengthened remastication. 



The mouth of the Camel seems formed to save for the animal 

 every drop of the fluid excretions of the nose : a channel leads 

 from each nostril to the mid-fissure dividing the upper lip, which 

 is continued down into the mouth. In the non-division and ex- 

 tensibility of the hair-clad upper lip, the Giraffe resembles the 

 Elk, but differs widely from that and every other ruminant in the 

 elegant tapering form of the muzzle. 



The Giraffe possesses great extensibility, flexibility, and ex- 

 traordinary command and power over the movements of its 

 tongue, fig. 144 ; its muscles are in number and kind as in other 

 Ruminants. The principal difference obtains in the greater ex- 

 tent of the organ, anterior to the insertion of the genio-glossus ; and 

 as this free and active part consists entirely of a firm muscular 

 tissue, invested by a thin but dense and very closely adhering 

 integument, there is a corresponding increase in the bulk of the 

 intrinsic as compared with those of the extrinsic muscles. Of 

 these the stylo-glossi, which are the principal retractors of the 

 free anterior part of the tongue, are relatively stronger than in 

 other Ruminants ; they arise by a tendon from near the lower 

 extremity of the stylo-hyal, and run forward, below the lateral 

 margins of the tongue, to which they are braced by a thin sheet 

 of fibres, descending obliquely forward from the sides of the 

 linguales to the upper margin of the stylo-glossi. The lingualis 

 inferior is a broad thin sheet of muscular fibres which comes off 

 from the condensed cellular tissue at the under part of the root 

 of the tongue and runs forward parallel with the fibres of the 

 stylo-glossi, with which it becomes blended anterior to the hyo- 

 glossi ; these accessory fibres cross the inner surface of the hyo- 

 glossus muscle, which is thus inclosed between the two layers of 

 longitudinal retractors. The arteries and veins of the tongue of 

 the Giraffe are not connected with a reservoir of blood, or with 

 any erectile tissue, as has been alleged. 1 The movements of the 



1 cxiv. p. 85. 



