338 



Glands open. The parotid, lined entirely by enzyme-secret- 

 ing epithelium, opens on the side of the cheek, while the 

 submaxillary gland, composed partly of acini with enzyme- 



secreting, and partly of acini 

 with mucin-secreting epithelium, 

 and the sublingual, composed 

 entirely of mucin-secreting acini, 

 open under the tongue (S.O.). 



The tongue in the horse is 

 smooth, but in the ox, and 

 still more markedly in the cat, 

 it is covered with a fine fur of 

 processes, the filiform papillae, 

 which are of use in passing the 

 food backwards along its sur- 

 face in the act of swallowing. 

 (For Organs of Taste, see p. 

 113.) 



Posteriorly, the mouth opens 

 into the pharynx (Ph.) or upper 

 part of the gullet. In the horse 

 the soft palate is very long, reach- 

 ing to the base of the epiglottis, 

 and, unless during swallowing, 

 shutting off the mouth from the 

 pharynx (fig. 148). On each 

 side, between the mouth and 

 the pharynx, is the tonsil (T.), 

 an almond like mass of lymph- 

 oid tissue. The pharynx is a 

 cavity which can be shut off 

 above from the posterior nares 

 by raising the soft palate, and 

 It is sur- 



FIG. 149. Diagram of the Parts of 

 the Alimentary Canal, from Mouth 

 to Anus. T, tonsils ; Ph., pharynx ; 

 S.G., salivary glands; Oe., oeso- 

 phagus ; C. , cardiac ; Py. , pyloric 

 portion of stomach ; D., duodenum ; 

 Li., liver; P., pancreas; J. , jeju- 

 num; /., ileum ; V. , vermiform 



appendix ; Col. , colon ; R., rectum. 



by pulling forward the posterior pharyngeal wall, 

 rounded by three constrictor muscles, which, by contracting 

 from above downwards, force the food down the gullet towards 

 the stomach. 



The (Esophagus (Oe.) is a muscular walled tube lined by a 

 stratified squamous epithelium. The muscles, below the lowest 

 constrictor of the pharynx, are of the visceral type, and are 



