THE SALIVARY GLANDS. 439 



lip, and pass beyond the commissures, to be spread for a short distance over the 

 inner aspect of the cheeks. It is easy, in the Hving Horse, after turning up the 

 lip and carefully wiping it, to see the salivary fluid secreted by these small organs 

 escape from their excretory ducts. 



Lingual Glandulce. — They form a layer under the mucous membrane at the 

 base of the tongue, and adhere very closely to the fibres of the small hyo-glossus 

 muscle, and, laterally, are continuous with the layer which covers the external 

 face of the amygdaloid mucous membrane. They are also found on the side of 

 the tongue, above the superior border of the great hyo-glossus muscle ; though 

 these are few and scattered, and look as if embedded in the substance of that 

 muscle. 



Staphyline Glandulce. — The thick layer these form under the anterior mucous 

 covering of the soft palate, has been described with that organ. We have only 

 to observe here, that it is continuous, laterally, with the glands at the base of the 

 tongue, through the medium of the glandulce of the amygdaloid cavity ; and in 

 such a manner, that the part of the mouth inmiediately in front of the isthmus 

 of the fauces, and which might be justly considered as the isthmus itself, is 

 enveloped in a complete glandular zone. In the dead body, we always find in 

 this compartment a variable quantity of viscid fluid, which is certainly secreted 

 in this zone. It is here, then, that the alimentary bolus is enveloped in the 

 glutinous matter intended to favour its passage in the pharynx and oesophagus ; 

 and it is worthy of notice that the constricted canal in which this secretion is 

 poured out in the living animal, immediately precedes the canal traversed by 

 the bolus of food in the act of deglutition. 



Differential Characters in the Salivary Glands of the other Animals. 



The salivary system of the Herbivora is more extensive than that of the Omnivora, and 

 especially the Carnivora. 



Ruminants. 1. Parotid gland. — The parotid glands of the Ox are distinguished by their 

 meagre development and red colour, whicli contrasts markedly with the pale yellow hue of the 

 maxillary glands. Tliose of the Camel have the same characters, and they are broader than 

 they are long. In tlisit animal, as well as in the Sheep and Goat, Steno's duct passes 

 through the mair^seter muscle. Moussu has seen the excito-motory nerve of the parotid, in the 

 Ox, become detached from the buccal nerve beneath the masseter muscle, become inflected on 

 the anterior border of that muscle, and pass backward and downward in the gland, following 

 Steno's duct. In the Sheep, the same origin and course ; consequently, the nerve passes on the 

 surface of the masseter, along with Steno's duct. It is often formed by two parallel filaments, 

 and is easily found and stimulated in order to produce the parotideal secretion. (In the Ox, 

 this gland offers, at the upper part of its anterior border, a round lobe lying on the masseter. 

 Steno's duct opens into the mouth at the fifth molar. It terminates in the Sheep and Goat 

 at the fourth molar.) 



2. Maxillary gland. — In the Ox, this gland is much thicker than in Solipeds, its volume 

 being in inverse relation to that of the parotid. In its posterior moiety it enlarges into an oval 

 lobe which, below the larynx, lies against that of the opposite side. Wharton's duct follows the 

 same course as in the Horse; the papilla through which it opens is hard, resisting, and 

 notched, and is lodged in an elliptical fossette near the incisors. 



The maxillnry gland of the Camel is slightly lobulated, and Wharton's duct docs not open 

 at the summit of the " barb," but at the base of the fraenum linguae by a kind of punched-out 

 opening. 



3. Sublingual gland. — In the Ox, Sheep, and Goat, this gland comprises two portions: a 

 posterior, somewhat voluminous and lobulated, provided with a .special excretory duct, which 

 follows and opens near Wharton's duct (by the ductus Bartholinianus) ; and an anterior, 

 pouring out its secretion by many canals, and representing the gland proper. This arrange- 

 ment allows the saliva to be collected separately from this gland. In the Camel, this gland 

 is very small, its lobules being also loosely agglomerated ; it has only multiple ducts, as in the 

 Horse. 



