THE VISCERA. 199 



auditory meatus, firmly united to it, before Proc. mastoideus, Mm. Sterno-cleido- 

 mast. and digastric, (post belly.) 



The internal edge is bounded by Proc. Styloideus and the muscles arising 

 from it Between this and m. pterygoideus internus we find a prolongation, 

 with a groove for Art. carotis externa. The superior border lies under Arcu$ 

 zygomat. and Artie, temporo-maxiUar. The inferior extremity fills the space 

 between angulus maxillar. inf. and m. sterno-cleido-mast. separated from the gl. 

 submaxillaris by a fibrous septum. 



Withinside the gland are situated, Artt. temporalis, transv. faciei, auriculares 

 anterr. ; V. facial, posterior N. facialis and its plexus anserinus ; N. auricular. 

 from plexus cervicalis, but superficial ; (red) lymphatic glands. 



Structure. Single acini are united into lobuli, which are held together by 

 the dense general envelope of the gl.parotis. 



The Excretory duct, ductus Stenonianus, arising from the associated ducts of 

 all the acini, passes out from the centre of the anterior border of the gland, 

 crosses horizontally forwards (below art. transv. faciei) five or six lines under 

 the zygoma, over the external surface, to the anterior border of the m. mas- 

 seter, curves at this point around a mass of fat, perforates it and m. buccinator 

 vertically, and passes for some lines between it 'and the mucous membrane, 

 until it opens in the region of the first and second molar teeth. It is thicker 

 at the anterior than at the posterior extremity; it consists of an internal (mu- 

 cous) and an external coat, and is rather extensible. At the posterior ex- 

 tremity a small lobule is sometimes attached, parotis accessoria. 



The vessels of the Parotis are numerous: Artt. are branches of the temporal., 

 transvers. and auricularis. Fi>., like the nerves, form a plexus parotideus, and 

 fall into V. facial, posterior. Vas. lymph, enter the lymphatic glands at the 

 angul. maxiil. and those before the external auditory meatus. 



Nerves: they are branches of plex. anserinus and N. auricular, anter. 



b. The submaxillary gland, glandula submaxiUaris, oblong, flat, bipartite, 

 placed, partly, on the internal surface of the basis max. inf., covered externally 

 and below by fasc. cervical, v. facial, ant., m. platysma myoides. and skin ; in- 

 ternally, by nerv. lingualis and hypoglossus and m. hyo-glossus, with a groove 

 (behind) for Art. maxillar. externa; meets behind with the post, belly of m. 

 digastricus surrounds in front the posterior border of m. mylo-hyoideus ; and 

 connected, above the last, with gl. subling., it gives off at this point its excre- 

 tory duct, the 



Ductus Whartonianus, shorter, more delicately membranous, but wider than 

 the d. Stenon., passes obliquely from below upwards, and from without in- 

 wards, parallel with n. hypogloss. and lingualis, at the commencement be- 

 tween m. myb-hyoideus (above this) and hyo-glossus, then between m. genio- 

 glossus and gl. sublingualis, on its internal surface, always close beneath the 

 mucous membrane, and opens at the sides of frenulum linguae in the papilUe 

 caruncula sublingualis, behind the inferior incisor teeth. 



Vessels : Artt. are branches of maxillar. externa., Vv. pass into the ven. facia- 

 lis anter. 



Nerves : they come from the gangl. maxillare nerv. lingualis. 



c. The sublingual glands, glandula sublingualis, small, oblong, flat, in a fossa 

 of the lower jaw close to Spina internamenti, projects inwards into the cavity 

 of the mouth, covered at this spot with mucous membrane only, close to the 

 frenulum they rest upon m. mylo-hyoideus (between the two gangl. sublinguak}; 

 the internal surface is directed towards m. genio-glossus and separated from 

 the last by N. lingualis, ductus Wharton., V. ranina. The anterior extremity of 



