THE SALIVARY GLANDS. 371 



their meagre development and red colour, which contrasts markedly with the pale yellow 

 hue of the maxillary glands. In the Sheep and Goat, Stenon's duct passes through tho 

 masseter muscle. (In the Ox, this gland offers, at the upper part of its anterior border, a 

 round lobe lying on the masseter. Stenon'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, residing, and notched, and is lodged in an elliptical fossette near the 

 incisors. 



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 Bartho- 

 linianus) ; and an anterior, pouring out its secretion by many canals, and representing 

 the gland proper. This arrangement allows the saliva to be collected separately from 

 this gland. 



4. Molar glands. These are more developed in Ruminants than in Solipeds. The 

 upper one is enlarged at its posterior extremity. 



PIG. The parotid gland of this animal is little developed, as in Kuminants, and 

 Stenon's duct follows the posterior border of the lower jaw. (Leyh says that it is, pro- 

 portionately, largely developed ; that its upper end does not reach the conch of tho ear, 

 and that Stenon's duct opens at the sixth molar.) 



The sublingual gland is analogous in its disposition to that of the Ox. Cuvier, in his 

 ' Lecons d'Anatomie Comparee,' indicates this : " The Pig has two sublingual glands. 

 One, very long and narrow, accompanies, outwardly, the excretory canal of the sub- 

 maxillary gland, from the angle of the jaw to the second sublingual. It is composed of 

 small lobules of a pale red colour. Its excretory duct arises near the posterior third, and 

 passes along with, but to the outside of, the submaxillary duct. It terminates near the 

 orifice of the latter by a small opening ; its diameter is equally small. The second sub- 

 lingual gland is placed before the first ; its form is square and flattened, and the lobes of 

 which it is composed are larger and redder. It has from eight to ten excretory ducts." (in 

 this animal the duct of Wharton does not open into the mouth by a papilla ; consequently 

 there is no barb.) 



CARNIVORA. The parotid of the Dog and Cat is small, and Stenon's duct always 

 passes through the masseter. (It opens at the fourth molar in the Dog, and the third in 

 the Cat.) 



In the Dog the submaxillary glands are larger than the parotids. " They even have 

 in front, along Wharton's duct, a small accessory gland, with a distinct excretory canal 

 opening into the same papilla as Wharton's." (Leyh states that the submaxillary duct 

 does not project into the mouth). The supplementary gland is absent in the Cat. 



The sublingual gland is not present in the Dog ; it is very small in the Oat, and 

 carried further back than in the other animals. (Leyh describes a bublingnal gland as 

 present in the Carnivora, and which is divided into two portions, as in the Pig : the 

 anterior being formed of detached lobules that open into the mouth by several ducts ; 

 and the posterior, larger above than below, with two ducts, the smaller opening into 

 Wharton's duct, and the larger a little in front of it.) 



The upper molar gland of the Dog, scarcely noticeable for the greater part of its 

 extent, forms posteriorly, under the zygomatic arch, near the eye, an independent lobe, 

 remarkable for its large size and its single excretory duct. Duvernoy who first 

 described it, proposed to name itthe subzygomatic gland. It is not present in the Cat. 

 (This is doubtless the organ described by Leyh as the orbital gland, which, he says, is 

 only found in the Dog; the superior molar gland, according to him, not existing in that 

 animal. This orbital gland is external to the ocular muscles, has three or four excretory 

 canals (the ductns Nucldani) which converge into one duct that opens into the mouth 

 above the last molar.) 



The labial, lingual, and palatine glandulx are much less developed in the Carnivora 

 than the Herbivora. This predominance of the salivary system in the latter is suffi- 

 ciently accounted for, when we consider the hard, fibrous, and coriaceous food these 

 animals live upon, and which must be ingested in large quantity, because of the small 

 amount of nutrition it contains. For its mastication and deglutition a great amount of 

 saliva is absolutely necessary. 



