264 SPECIAL HISTOLOGY. 



instance in the superior belly of the omohyoid, in a portion 

 of which, three inches long, the space over which the nerves 

 are distributed, does not exceed from five to eight lines in 

 length. The trunk of the nerve entering in the middle of the 

 transverse axis, divides into two equal primary branches, one 

 passing towards the left, and the other towards the right 

 border of the muscle, and each giving rise to numerous anas- 

 tomosing branches of all sizes, and thus supplying the entire 

 thickness of the muscle from the most superficial to the 

 deepest layers. Whilst this distribution of tbe nerve takes 

 place at one point, — a distribution not unlike that in an organ 

 of sense, — the rest of the muscle presents the utmost poverty, 

 or even a complete deficiency of nerves. In one case, which 

 I examined closely, I was unable, besides the few vascular 

 nerves in these portions, to detect more than three small 

 nervous twigs of 0-021'", O028'", O042"', which, though de- 

 rived from the main nerves, differed from the other branches 

 in their distribution. Two of them ran directly towards the 

 lower, and one towards the upper end of the belly of the 

 muscle, giving off a few filaments composed of one or two 

 primitive fibrils which passed through the muscle, and termi- 

 nated, a little oefore reaching the intermediate and terminal 

 tendons, in the most minute twigs and single nerve fibrils. 

 I found the same conditions of the nerves in the suhcruralis, 

 and in one of the costo-cervical muscles (arising from the first 

 rib in the cervical fascia), as in the omohyoid ; in the sterno- 

 hyoid, sternothyroid, omohyoid (inferior belly), the same con- 

 dition in some parts was noticed, whilst in others, one appa- 

 rently different, existed, that is to say, the branches of the 

 nerves frequently did not all divide at the same level, but were 

 more widely spread. It was easily seen, however, that the 

 above-described mode of division essentially obtained, also, in 

 this case, viz. that the separate portions of the muscles are in con- 

 nection with the nervous plexuses, only at a point of limited extent. 

 The proof of the existence of similar conditions in other small 

 muscles was more difficult, as in those of the orbit, where the 

 nerves reach the muscles at acute angles, follow a longer course 

 in them, with their primary branches, and form their ultimate 

 ramifications at various, more or less widely separated points ; 

 yet even in this case it was tolerably well made out. It is 



