THF ALIMENTARY CANAL. 223 
The sides of the mouth cavity are formed by the teeth and 
the gums, covering the alveolar borders of the mandible, 
maxillaries, and premaxillaries. 
The mouth cavity presents further for examination the 
glands, the teeth, the tongue, and the soft palate. 
THE GLANDS OF THE MOUTH (GLANDULA ORIS).— 
There are five pairs of salivary glands which open into the 
mouth cavity. 
1. The parotid gland (glandula parotis) (Fig. 65, 1; Fig. 
131, 10) is flattened, rather finely lobulated, and lies ventrad of 
the external auditory meatus and beneath the derma! muscles. 
Its cranial border follows the caudal border of the masseter 
muscle and overlies it somewhat; its caudal border is about 
three centimeters caudad of the border of the masseter. Its 
borders are unevenly lobed. The parotid duct (ductus paro- 
tideus: frequently called Stenon’s or Steno’s duct) is formed 
by the union of several smaller ducts near the ventral end of 
the cranial border of the gland. It passes craniad imbedded 
in the fascia covering the masseter. At the cranial border of 
the masseter it turns inward and lies close against the mucous 
membrane of the mouth, so that from the inside of the mouth 
it appears as a white ridge on the mucosa. It opens on the 
inside of the cheek opposite the most prominent cusp of the last 
premolar tooth. Along the course of the parotid duct in some 
cases one or more small accessory parotid glands are found. 
2. The submaxillary gland (glandula submaxillaris) 
(Fig. 65, 2, page 109, and Fig. 131, 11) is approximately kid- 
ney-shaped. Its surface is nearly smooth, the lobulations not 
being apparent externally. It lies ventrad of the parotid, at 
the caudal edge of the masseter muscle, just caudad of the 
angular process of the mandible. The posterior facial vein 
(Fig. 131, 6) crosses its outer surface, and its cranioventral 
border is hidden by two lymphatic glands (Fig. 131, 12) lying 
at the sides of the anterior facial vein. The submaxillary 
duct (ductus submazxillaris, frequently called Wharton’s duct) 
leaves the inner surface of the gland and passes beneath the 
digastric and mylohyoid muscles and against the outer surface 
of the styloglossus. From the point where the styloglossus 
