348 SHOULDER-GIRDLE IN MONOTREMES, 



cervical nerve, to supply the sterno-niastoid muscle (2). Con- 

 tinuing on its course the main trunk of the nerve receives a branch 

 from the second cervical nerve (5), and also from the third cervical 

 (6), and piercing through the anterior part of the trapezius it 

 supplies it (8), and ends in the posterior portion of this muscle (7). 



JV. hyj)oglossus (13). After emerging from the skull this nerve 

 runs towards the median ventral line, where it supjDlies the hyoid 

 muscles and gives off a large branch which runs posteriorly, and 

 receives branches from the first (13a) and rsecond (14) cervical 

 nerves, after which it gives otf a twig to supply the omohyoid (15); 

 and running towards the median ventral line it x'eaches almost to 

 the presternum. 



N. phrenictis (17) springs from the third cervical nerve. Pass- 

 ing posterior it obtains branches from the fourth cervical (17a) and 

 the fifth cervical, and also two thin twigs from the nerve to the 

 subclavius (21). 



jV. cervicalis ^., is small, and after giving off a branch (13a) to 

 the descending part of the hypoglossus, ends in muscular branches. 



iV". cervicalis ii., considerably larger than the first, gives off a 

 branch (5) (14) to the descending part of the hypoglossus, and a 

 branch to the spinal accessory ; al.so one which joins a branch 

 from the spinal accessory to the sterno-mastoid (2) ; a twig to a 

 branch from the third ; and some twigs which run to the auricular 

 region; while the nerve terminat^'S about the mid-ventral line, by 

 breaking up into numerous fine cutmeous branches. Besides 

 these branches the second nerve gives off a large branch which, 

 after supplying the "dorsal part of the acromio-trachelien (U)," 

 joins with a branch from the third cervical nerve to form the 

 nerve to the rhomboid (9). 



JV. cervicalis Hi. This divides into two branches. The anterior 

 of these sends off immediately a branch which, after supplying the 

 ventral portion of the acromio-trachelien (12), continues on, and 

 joining the branch from the second nerve, forn)s the nerve to the 

 rhomboid (9). The anterior division runs outwards and breaks 

 up into numerous twigs which supply the side of the neck and 

 communicate with branches from other nerves (6, 10). 



