232 



PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



the food and draw it within the mouth. The extrinsic muscles are 

 connected with the hyoid bone and chin, and render possible the pro- 

 trusion and retraction of the tongue ; the intrinsic muscles permit of 



Fig. 81.— After Gamgee and Chauveatj. 



1 and 2, auricular muscles ; 3, scutiform cartilage : 4, external scuto-auricular muscle ; A A, auric- 

 ular branches of first pair of cervical nerves ;BB, anterior auricular nerves ; C, terminal fibres of the 

 supraorbital nerve ; D. superficial branch of the lachrymal nerve ; Y, tendon of muscle to elevate upper 

 lip; Z, naso-transversalis muscle. 



the change of shape of the tongue required in mastication and deglu- 

 tition. The tongue is, further, covered with a mucous membrane, on 

 the dorsal surface of which are numerous more or less horny papillae) 



