238 Anatomy of the Rabbit. 



In addition to the tributaries described above, the anterior 

 facial vein receives from beneath the anterior margin of the 

 masseter the deep facial vein (v. facialis profunda). The latter 

 arises in the lower anterior portion of the orbit, and passes down- 

 ward beneath the masseter muscle. The anterior facial vein 

 receives at the ventral border of the mandible the internal max- 

 illary vein (v. maxillaris interna). The latter also begins in the 

 orbit, where it is connected with the deep facial. At the medial 

 surface of the mandible it receives the inferior alveolar vein — to 

 be seen at a later stage — from the interior of the mandible. 



The external jugular vein may be divided and turned forward together with 

 the parotid gland. 



4. Examination of the more superficial structures of the ventral 

 surface of the head and neck. 



(a) The submaxillary gland (gl. submaxillaris) , one of the 

 \/ salivary series, a somewhat compact rounded or oval gland 



lying at the medial side of the extreme ventral portion of the 

 angle of the mandible. Its whitish -colored duct (d. sub- 

 maxillaris) may be seen running upward and slightly for- 

 ward, to enter the mouth. It crosses the lateral surface of the 

 digastric muscle but is medial to the external maxillary 

 artery. 



(b) The angle of the mandible is covered by two muscles of 

 mastication, the masseter lying on the lateral surface, and 



y. the pterygoideus internus on the medial surface. 



(c) The digastricus. Only its insertion portion is visible. It 

 passes forward along the medial surface of the mandible, to 

 the anterior portion of which it is attached. 



(d) The mylohyoideus is a transverse sheet of muscle arising 

 from the medial surface of the mandible on either side and 

 inserted on the hyoid bone. 



(e) The sternomastoideus. Origin: In common with that 

 of the opposite side, from the manubrium sterni. Insertion: 

 Mastoid, process of the skull. 



(f) The sternohyoideus. Origin: In common with that of the 

 opposite side, from the dorsal surface of the manubrium and 

 an terior portion of the body of the sternum, extending to the 

 third costal articulation. Insertion: Greater cornu ot the 

 hyoid. 



