372 



THE DIGESTIVE APPARATUS IN MAMMALIA. 



COMPARISON OF THE SALIVARY GLANDS OP MAN WITH THOSE OP ANIMALS. 



As in animals, the parotid is the most voluminous of the salivary glands. Its tissue 

 is reddish-grey and lobulated, the lobules adhering closely to each other. Its shape is 

 irregular, and it is moulded to the excavation behind the angle of the jaw. Stenon's 

 duct passes across the masseter, and shows on its course some salivary lobules, formin- 

 what is named the accessory parotid (or soda parotidis) ; it opens opposite the third 

 upper molar. 



The submaxillary gland weighs about half-an- ounce. It is partly situated beneath 

 the deep cervical fascia, and partly within the body of the lower jaw, between the mylo- 

 hyoideus and hyo-glossus muscles. Its lobules are more loosely united than those of the 

 parotid. Wharfon'e duct opens on the sides of the frsenum linguae by a small opening at 

 the apex of a round papilla (caruncula sublingualis). 



The sublingual gland is analogous to that of the Ox and Pig. There are, in fact, two 

 sublinguals ; an anterior about the size of an almond, and furnished with a single 

 excretory canal the ductus Bartholini, that terminates near Wharton's duct; the other, 

 posterior, formed by several isolated lobules with multiple excretory ducts, the ductus 

 Hiviniani. 



There are also labial, palatine, and lingual glands ; with, besides, near the frsenum, 

 a small conglomerate gland, the gland of Nuhn, which has a special duct. 



Fig. 174. 



PHARYNGEAL AND LARYNGEAL RE- 

 GION ; THE POSTERIOR PART OF 

 THE HEAD INCISED AND THROWN 

 FORWARD. 



1, Base of the cranium ; 2, Roof of 

 the pharynx ; 3, Muscles of the 

 cheek ; 4, 4, Walls of the pharynx ; 

 6, Septum nasi ; 7, Posterior 

 openings of nostrils ; 8, Entrance 

 to the mouth ; 9, Epiglottis ; 10, 

 Posterior pillars of soft palate ; 11, 

 Arytenoid cartilages ; 12, Opening 

 of the oesophagus ; 13, (Esophagus ; 

 14, Trachea. 



THE PHARYNX. (FigS. 174, 175.) 



Preparation. 1. Study the general disposition 

 and situation of this vestibule in the antero- 



rsterior vertical section of the head (fig. 175). 

 In order to examine the interior conveniently, 

 the head should be separated from the neck, 

 leaving attached to it a certain portion of the 

 trachea and oesophagus ; then by sawing across, 

 either through or behind the temporo-maxillary 

 articulations, all that portion of the cranium is re- 

 moved, and the posterior parietes of the pharynx is 

 exposed, and may be dissected to study the muscles 

 (Fig. 178), or opened in the middle line to reach 

 the interior of the cavity (Fig. 174). 3. The muscles 

 should be dissected with those of the tongue, and 

 in the same manner. 



The pharynx is a membranous vestibule 

 common to the digestive and air passages, 

 and situated behind the soft palate, which 

 separates it from the mouth ; above, it is at- 

 tached to the base of the cranium, and, below, 

 to the laryngeal apparatus. 



Form and internal disposition. In con- 

 sequence of the conformation of the soft 

 palate, which, in the domesticated animals, 

 and particularly in Solipeds, is prolonged to 

 the base of the epiglottis, the pharynx forms 

 a cylindrical cavity elongated from before to 

 behind, enclosed laterally and posteriorly 

 by wide thin muscles, and with the soft 

 palate for an anterior wall. At the two 

 extremities of this cavity are openings which 

 allow the pharynx to communicate with the 

 other passages or cavities, and whose dis- 

 position we will at once begin to study. 



At the upper extremity of the large 

 axis of the pharyngcal cavity is to be re- 

 marked: 1, In front, the two posterior 



