No. I.] THE CRANIAL NERVES OF AMPHIBIA. 143 



ous distribution. The main nerve ip) now proceeds cephalad 

 under one of the gill bars, a blood-vessel lying below it. At 

 822 it sends a branch around outside the cartilage to its dorsal 

 side. At "jZZ the remainder assumes the same position. Its 

 distribution is partly to the gill-raker attached to the dorsal 

 side of the cartilage. Ganglion cells appear in it in places along 

 its course, especially as it nears the point where the gill mem- 

 brane is merged with the pharyngeal mucous membrane. Here 

 (690 ±) the nerve lies in the floor of the pharynx, near the heart. 

 It breaks up here, part of it turning caudad, and all of it being 

 distributed, as far as could be observed, to the pharyngeal 

 epithelium. It is obviously a R. branchialis . 



Returning to 910, the dorsal of the two divisions (7) receives 

 a short, reenforcing branch from the other, and proceeds 

 cephalad and ectad as far as 840 ±, where it proceeds ventrad 

 along the dorsal and outer side of the blood-vessel and turns 

 caudad, still proceeding ventrad and thus rounding one of the 

 Mm. levatores, where it again turns cephalad. This nerve con- 

 tains two very large and prominent fibres. As it turns (870 ±) it 

 gives off a twig (/ a) containing these two coarse -fibres, together 

 with a number of smaller ones. It is evident that this twig 

 resembles the one (p c) given off from the preceding nerve, 

 which could not be traced. This twig is larger, however, and 

 can be traced to its distribution. It divides just subsequently 

 to its separation. One portion {y a^, containing one of the 

 coarse fibres, proceeds cephalad around the angle of the 

 branchial cavity, through a thin muscle in the body wall, and 

 thus becomes subcutaneous. It does not appear to give any 

 fibres to the muscle, and is distributed to the skin. This divi- 

 sion of the twig is thus probably of the "general cutaneous" 

 type. The other division {y a^ rounds the angle of the body 

 cavity at 777, and is in every way similar to y a^. After giving 

 off this twig, the main nerve (7) passes under one of the gill 

 bars — the one next to the one under which the last-described 

 branch ran. At 807 a fibre or two comes off, which proceeds 

 ventrad, but could be traced only a few sections. At y6y a 

 small branch separates, which could be traced cephalad some 

 distance, running near a blood vessel. At 613 the nerve. 



