

154 MAMMALIA. 



then becomes the circumflex to pass outwardly to the muscle corresponding with the 

 deltoid, and send a branch over the external head of the triceps, to pass down the arm 

 to the skin. Branches proceeding from the external branches of the second and third 

 dorsal nerves supply the skin of the arm like the smaller internal cutaneous. The 

 internal cutaneous proceeds from the ulnar. The usual musculo-cutaneous arises 

 principally from the sixth cervical nerve and a small branch of the seventh ; it sends a 

 branch to the median ; it supplies and then pierces the coraco-brachial muscle to 

 terminate on the biceps. The median nerve arises from the seventh cervical and first 

 dorsal nerves, and receives a branch from the musculo-cutaneous ; it sends a branch on 

 the outer side of the biceps, to supply the internal brachial muscle, and the skin at the 

 posterior and inner part of the fore-arm, instead of the radial branch of the spiral, and 

 the usual branch of the external cutaneous. The median, after supplying the flexor 

 muscles placed in the fore-arm, sends a slender nerve close to the bone, which gives 

 filaments to the periosteum, and passes to a muscle analogous to the long flexor of the 

 thumb; it then passes underneath the annular ligament, and sends a large branch 

 obliquely over the flexor tendons, to communicate with the ulnar, and descends, giving 

 off branches to the skin at the inner side of the foot, which communicate with the 

 inner portion of the deep palmar of the ulnar ; it then passes into the foot covered by 

 the membranous plaits attached to the hoof to terminate on these, the villous part of 

 the sole and the ligaments of the joints. In the jaguar the median nerve passes 

 through a foramen in the bone of the humerus with the humeral artery. In the ass 

 the ulnar arises from the seventh cervical and first dorsal nerves ; at the middle of the 

 arm it sends off the internal cutaneous nerve, and at the elbow gives some branches to 

 the ulnar muscle and the elbow-joint ; it passes down, covered by some fibres of the 

 flexor muscles ; and at the wrist sends off the dorsal branch to the skin at the posterior 

 and outer part of the fore-arm ; it passes underneath and to the inner side of the ulnar 

 flexor, and then underneath the annular ligament, and gives off the deep palmar nerve ; 

 it receives the branch from the median and descends, giving branches to the skin and 

 ligaments at the outer side of the foot, after these have communicated with the outer 

 branch of the deep palmar ; it passes into the foot, covered by the membranous plaits 



