122 EQUINE ANATOMY. 



above and below, the intermediate four in the upper and two in 

 the lower. 



SALIVARY GLANDS. 



These secrete saliva, which exerts a chemical and mechanical 

 action on the food m the mouth, into which the secretion is 

 poured. 



They are the parotid, sub-maxillary, sublingual, molar, labial, 

 lingual and palatine. 



The parotid lies behind the angle of the lower jaw, is the 

 largest, and its duct (Steno's) opens opposite the third upper 

 molar. 



The sub- maxillary^ lies in the intermaxillary space outside the 

 larynx, its duct (Wharton's) opens at the side of the fraenum on 

 a small tubercle, the barb. 



The sublingual lies in the intermaxillary space, under the 

 tongue, its ducts (of Rivinian), 15 to 20, open near that of 

 Wharton on a ridge. 



The molar are two on each side opposite the molar teeth. 



PHARYNX. 



The pharynx is an elongated cavity behind and above the 

 mouth and nasal cavities. 



Coats. 



Muscular, see Muscles. 



Mucous of basement membrane, covered above with ciliated 

 and below with flattened epithelium. 



Openings, y. 



In front iwo posterior nares, two Eustachian tubes, and isthmus 

 of the fauces. 



Below, the tops of the oesophagus and larynx. 



Vessels. — Pharyngeal and thyroidal arteries. 



Nerves. — Ninth, tenth and sympathetic. 



CESOPHAGUS. 



The oesophagus is a long, narrow muscular canal beginning at 

 the pharynx, passes through the thorax, deviating to the left, 

 channels the lungs, passes through a special opening in the dia- 

 phragm, and ends in the cardiac extremity of the stomach. 



Coats. 



Muscular. — Superficial, longitudinal and deep circular fibres, 

 the upper half are striped, the remainder unstriped. 



