694 ALLIS. [Vou. XII. 
outward, internal to, and then outward and downward, behind, 
the levator arc. branch. int. post. (to which muscle, in one dis- 
section (Fig. 52, Pl. XXXIV), it sent a delicate nerve, appar- 
ently innervating it in part), and then separates into an anterior 
and a posterior portion. The former, or ramus anterior n. 
vagi secundi, turns forward along the outer surface of the 
levator, and gives off three branches which together constitute 
the ramus pretrematicus of the nerve (pvv?). The remainder 
of the nerve continues forward, as the ramus pharyngeus n. 
vagi secundi (fv?), passes through the large oval opening 
between the two ligaments connecting the epibranchial of the 
second arch with the infrapharyngobranchial and epibranchial 
of the third arch, and then turns inward and forward between 
the second and third infrapharyngobranchials, and is distrib- 
uted to tissues there. The three branches which together 
constitute the ramus pretrematicus of the nerve, the ramus 
branchialis posterior arci secundi of Stannius, run outward and 
downward close against the posterior surface of the levator arc. 
branch. ext. secundus, reach the upper surface of the second 
arch beyond the insertion of that muscle, and have the course 
and distribution already given. 
The posterior portion of the nerve, the ramus posttrematicus 
n. vagi secundi (fsv2), gives off from its base two nerves, one 
of which runs directly to the levator arc. branch. ext. tertius, 
which it innervates, and the other to the levator arc. branch. 
ext. quartus, which it innervates in part, but in part only, for 
the muscle receives also an important branch from the posttre- 
matic branch of the third vagus, which runs downward and 
outward to the upper and posterior surface of the muscle. 
From this latter nerve a terminal branch is sent into the 
adductor muscle that lies between the epibranchial and cerato- 
branchial of the fourth arch. 
After giving off the two branches described above, the ramus 
posttrematicus secundus runs outward and downward in front 
of the levator of the third arch, reaches the dorsal surface of 
the arch, sends an anterior branch to the dorsal surface of the 
ceratobranchial of the arch, and is joined by two or three 
nerves, which together constitute the ramus pretrematicus n. 

