BY W. J. S. McKAY. 351 



37. N. to p. quartus, which receives a biuach ot" communicatioa 

 from the second intercostal. 



47. N. musculo-cutaneus. 



48. N. to biceps. 



49. N. to M. coraco-brachialis longus. 

 49a. N. to M. coraco-brachialis brevis. 



42. Cord to median nerve. 



The second part of the anterior cord of the vii. nerve first gives 

 a branch which communicates with the nerve to the latissimus 

 dorsi. The cord then continues its course and gives off a large 

 cutaneous branch (45) to the forearm (flexor surface). Then 



40a. N. to the dorso-epitrochlear. 

 44. N. musculo-spiralis. 

 44a. Branch to triceps (scapular head). 

 44b. Branch to triceps (humeral heads). 

 46. N. ulnaris. 



43. Cord to median nerve (41). 



The posterior of the two divisions, that the seventh nerve 

 divides into, runs to join the cord formed by the viii. cervical 

 and i. and ii. dorsal nerves. The resulting cord (54) then divides 

 into two main divisions (56, 57) ; both these divisions now break 

 up into numerous branches, some of which are joined by twigs 

 from the intercostal nerves, and thus is formed a very complicated 

 network distributed over the lateral and ventral aspects of the 

 thora.K and abdomen. 



This cord (54) and its numerous branches we take to be the 

 "lateral cutaneous nerve of the thorax," of Patterson [16], who 

 considers it to represent the *' nerve of Wrisberg." In a careful 

 dissection of the Opossum (Trichosurus vidpeculaj recently made 

 by us, no nerve of Wrisberg was present; the second intercostal 

 and the third intercostal sent branches down the arm and forearm, 



