320 H. W. NORRIS 
ing antero-ventrally, after giving off its communis fibers chiefly 
to the ventral wall of the pharynx (X.1,pst.ph.), and some small 
motor branches to mm. subarcualis rectus (sar.) and subarcualis 
obliquus 1 (sao.1), its main motor portion joins the ramus post- 
trematicus IX to innervate the ceratohyoideus internus muscle. 
Driiner says that musculus subarcualis obliquus 2 is innervated 
by a branch of this nerve, but the writer has not confirmed this 
with certainty. (3) A third branch of general cutaneous and 
communis fibers (br.2,X.1) turns out over the top of ceratobranch- 
ial 2 and, after receiving a small anastomosis from the third 
branchial nerve, is distributed to the second gill. Fischer 
considered the second branchial nerve as a part of the glossopha- 
ryngeus. Wilder (1. c., p. 668) says: ‘‘the entire 2nd. external 
gill, including its muscles, is supplied by a branch of the glosso- 
pharyngeus. ”’ 
The pharyngeal branch of the second branchial nerve (figs. 48, 
44, X.1,ph.), after running posteriorly some distance, turns upon 
itself and passes anteriorly and ventrally along the dorsal wall 
of the pharynx. At the point where it turns anteriorly it gives 
off a ramus pretrematicus (X./,prt.) which ascends around the 
dorso-lateral angle of the pharynx to reach the medial border 
of the first branchial arch (ceratobranchial 1), along which it 
passes antero-ventrally. Other small pharyngeal branches may 
be distributed to the dorsal pharynx wall immediately posterior 
to the origin of the ramus pretrematicus. 
7. The third branchial nerve 
This nerve (figs. 42-44, X.2) leaves the ganglion at the medial 
border of, and slightly posterior to the origin of the second bran- 
chial nerve. Very early a differentiation of a ventral pharyngeal 
branch from a more dorsal portion is indicated, although the 
actual separation may be deferred until well back in the branchial 
region. The dorsal portion of the nerve divides into two parts, 
one of which, the more ventral, passes posteriorly between the 
levator arcus branchialis 2 and levator arcus branchialis 3 muscles, 
more posteriorly between the latter muscle and the second cerato- 
branchial cartilage, and divides into two branches which curve 
