S6 TKANSACTIONS OF THE [jAN. 11, 



surface of the muscle to the auricular region, breaking up into 

 a leash of branches as it approaches the terminal distribution. 

 These branches follow, in all species examined, a regular arrange- 

 ment, the plan of which is indicated in Plate VI., Tig. IV. 



1. The most posterior or dorsal branch (Fig. IV., 1) supplies 

 the integument of the retro-auricular and mastoid regions, ex- 

 tending over the occipital attachment of the Trapezius and 

 anastomosing with the Occiptalis major. This branch supplies 

 the region usually innervated by the human Occipitalis minor. 



2. The second terminal branch (Fig. IV., 2) is usually the 

 largest. It runs in the cranio-auricular groove, giving branches 

 to the mastoid region, to the cranial surface of the anterior helix 

 margin, and to the cranial surface of the cymba and cavitas 

 conchse. 



3. The third branch (Fig. IV., 3) supplies the back part of 

 the cymba (cavitas inferior conchae). 



4. The fourth branch (Fig. IV., 4) supplies the integument of 

 the inferior and anterior surface of the external auditory meatus. 



5 and 6. The fifth and sixth branches (Fig. IV., 5, 6) supply 

 the integument over the parotid region in front and below the 

 external auditory meatus. 



II. N. Cervicalis superficialis. 



This is composed of an ascending dioision, derived from the 

 Third Cervical nerve (Plate VI., Fig. I., 10), and a transverse 

 division^ derived from the Third and Fourth cervical nerves. 

 (Fig. I., 10'.) 



1. The ascending division (Plate VI., Fig. IV., 7, 8, 10) sends 

 a twig (Fig. IV., 7) to the integument of the parotid region, in 

 front of the external auditory meatus, between it and the can- 

 dyle of the lower jaw. 



The continuation of the nerve divides into two branches (Fig. 

 IV., 8, 10), which pass obliquely upwards to the anterior margin 

 of the parotid gland and to the angle of the jaw, meeting the 

 infra-maxillary branches of the Facial Nerve and anastomosing 

 freely with them at their point of emergence from the gland and 

 along the margin of the mandible. One of the branches (Fig. 

 IV., 10) continues obliquely across the Masseter muscle to the 

 integument overlying the buccal pouch. 



2. The transverse division, derived from the third and fourth 

 cervical nerves, emerges from the cover of the Sterno-mastoid at 

 a somewhat lower level, usually combined wtth the Supra-sternal 

 and internal Supra-clavicular descending branches of the Fourth 

 nerve (Fig. III.). Passing underneath the external jugular 



