1S87.J 



ANATOMY OF HYDROMYS. 



59 



off the greater portion of the anterior thoracic nerve. The Gth nerve 

 divides into two portions, an npper and lower. The combined cord 

 formed by the 7th cervical and 1st dorsal also divides into two 



Fig. 1. 





M.Sr 



Cervical and brachial neryes. (Diagrammatic.) 



1-7. Cervical nerves; LB. 1st dorsal nerve; Sp.Sc. Suprascapular ; Sb.Sc. Sub- 

 scapular ; CfLr. Circumflex; Tl/.C. Musculo-cutaneous ; Tr. Nerve to tri- 

 ceps; M.Sp. Musculo-spiral ; U. Ulnar; M. Median; C'u. Internal cuta- 

 neous ; Phr. Phrenic ; Tk. Anterior thoracic ; M.M. Muscular branches. 



portions, an anterior and a posterior. The upper part of the sixth, 

 having received the branch from the circumflex, joins the anterior 

 part of 7 + 1, and the combined trunk becomes musculo-spiral, having 

 previously given oflF branches to the triceps and other muscles. The 

 lower division of 6 joins the posterior of 7+ 1, having first given off 

 a filament which joins the anterior thoracic. The large trunk thus 

 formed, having given off some muscular branches, splits up into ulnar, 

 median, and internal cutaneous. 



Lumbosacral Nerves (fig. 2).— The 1st lumbar forms the ilio- 

 hypogastric and the 2nd the ilio-inguinal. These nerves are 

 connected with one another by a communicating branch, but have no 

 junction with those below. The 3rd gives off genito-crural, a 

 branch of communication with 4, and in conjunction with a branch 

 from this last forms external cutaneous. Tlie remaining portion of 

 4 with a branch from 5 forms a common trunk which divides into 

 obturator and anterior crural. The great sciatic is formed by the 



