324 H. W. NORRIS 
the intestino-accessorius it gives off from its posterior border a 
nerve to the omo-arcualis muscle (oma.), and a little anterior, 
after the division, it supplies the dorso-laryngeus muscle with 
a number of small twigs (dl. 3). Wilder states that the 
omo-arcualis (procoraco-branchialis) is innervated by the ramus 
lateralis ventralis. 
9. The ramus recurrens sensitivus X 
Leaving the lateral border of the extreme posterior end of the 
vagus ganglion, in close association with the ramus intestino- 
accessorius in origin, is a nerve, of communis composition, al- 
though it may have a few motor fibers (dl./), which form a second 
small nerve running to the dorsal portion of the dorso-laryngeus 
muscle. It runs on the ventral border of the great bundle of 
nerves issuing from the posterior end of the vagus ganglion (fig. 
40, s-r.). It may be asingle trunk, or its main branches may arise 
separately from the ganglion. At about the level where the sec- 
ond branchial pretrematic ramus (X./ prt.) is formed there is 
given off a nerve (fig. 43, s-r.1), which sends one or more branches 
along the dorsal pharyngeal epithelium. An anastomosis may 
be formed with the pretrematic ramus of the fourth branchial 
nerve (X.3 prt.). At about the level of the formation of the third 
branchial pretrematic ramus (X.2,prt.) another branch (s-r.2) 
arises which divides into two nerves, both passing posteriorly 
and ventrally between the two levator muscles of the third and 
fourth branchial arches, to take a position on the medial border 
of the fourth ceratobranchial, following it antero-ventrally, thus 
constituting a fifth branchial pretrematic ramus (X.4,prt.). The 
main trunk of the nerve, which at first runs at the ventral border 
of the great nerve bundle, farther posteriorly begins to pass dor- 
sally along the dorsal border of the trapezius muscle, later passing 
between the latter and the levator muscle of the fourth branchial 
arch. At the anterior border of the dorso-laryngeus muscle the 
nerve passes between this muscle and the levator arcus branchia- 
lis 4 muscle, then, curving ventrally between the same two mus- 
cles, it turns anteriorly into the ventral branchial region, its later 
course for some distance paralleling approximately that of the 
