150 MAMMALIA. 



dorsal nerves is seldom fewer but often greater than in man, and varies with that of 

 the dorsal vertebrae and ribs ; the number of lumbar, sacral, and caudal, varies with 

 the corresponding portions of the spine ; the anterior trunks of the lower sacral and 

 caudal nerves form an anterior caudal nerve on each side, whilst the posterior form the 

 posterior. 



Each nerve, after the union of the anterior bundle with the posterior beyond the 

 ganglion, is divided into an anterior and posterior trunk ; the anterior is generally by 

 far the largest, and furnishes many branches to parts situated near it, and enters into 

 the principal plexuses, as the axillary, sciatic, and others ; the posterior is generally 

 small, but varies with the quantity of muscles and skin supplied by it. The nerves in 

 all the mammalia are distributed to corresponding parts, but are larger or smaller 

 according to the magnitude of the skeleton, or of particular organs. 



In the fox, the sub-occipital nerve emerges from a foramen in the atlas ; the 

 anterior trunk passes forwards, and sends up two filaments to the junction of the trunk 

 of the par vagum with the glosso-pharyngeal, the ninth, accessory, and the superior 

 cervical ganglion of the sympathetic ; it gives branches to the anterior straight muscles 

 of the head, and then joins the slender descending branch of the ninth, to be distri- 

 buted on the sterno-hyoid and thyroid muscles ; the posterior trunk terminates on the 

 posterior straight and oblique muscles. In the ass, several branches from the superior 

 cervical ganglion of the sympathetic, in a plexiform manner, join the anterior trunk of 

 the sub-occipital ; the small descending branch of the ninth communicates either with 

 the trunk or a filament from the par vagum, before it joins the anterior trunk of the 

 sub-occipital ; afterwards it communicates with the pharyngeal plexus, and is then 

 distributed on the sterno-hyoid and sterno-thyroid muscles. 



In the fox, the anterior trunks of the first and second cervical nerves give branches 

 to the anterior straight muscles of the head, and then unite to communicate with the 

 accessory, and divide into branches, which are distributed on the cutaneous muscle and 

 skin, at the side of the face and neck and external ear. The third gives a branch to 

 join the accessory and others to the trapezius muscle, and is then distributed on the 

 cutaneous muscle and skin at the side of the neck. The fourth gives a branch to the 



