Herrick, Merves of Stluroid Fishes. IgI 
- articular bone and farther cephalad between the dentary bone 
and MEcKEL’s cartilage. In the latter position it crosses inter- 
nal to the r. mandibularis V, with which however it does not 
anastomose, and then enters the bony lateral line canal in the 
dentary bone, innervating there its first and second canal organs. 
The organs of the operculo-mandibular canal are innervated by 
successive branches of this nerve as shown on Fig. 1, and no 
branches were traced to pit organs or any other distribution. 
The cutaneous branch, on the other hand, supplies no canal 
organs. Its chief distribution is to small pit organs, large pit 
organs and terminal buds of the skin dorsal and external to the 
operculo-mandibular canal, though, as we have seen, the 
proximal portion carries general cutaneous fibers also for the 
outer skin adjacent to the canal behind the eye. This nerve 
runs cephalad near the skin under the ventral edge of the m. 
adductor mandibulae, then under the skin of the lateral face of 
the mandible, slightly dorsally of the course of the main r. 
mandibularis internus VII. It gives off numerous small branch- 
lets for the small pit organs freely distributed along its course 
and also for a number of large pit organs which are scattered 
along the course of the canal, as shown in Fig. 1. The most 
caudal half dozen of these large pit organs are arranged in an 
irregular line running obliquely caudad and dorsad above the 
opercular canal and correspond to the cheek line of pit organs 
shown in Fig. 14. The cutaneous branch apparently carries 
general cutaneous fibers no farther cephalad than the eye, and 
in the mandible it follows closely the ventral side of a large 
cutaneous twig of the r. mandibularis V, from which the gen- 
eral cutaneous nerve supply of this region is derived. Com- 
munis fibers, on the other hand, appear to accompany this nerve 
to its ultimate ramifications, and terminal twigs from most of 
its branches were definitely traced into both small pit organs 
and terminal buds. 
COLLINGE ('95, p. 281) makes the surprising statement 
that the mandibular canal of A. catus is supplied by the exter- 
nal ramus of the r. mandibularis V. This is certainly not true 
for Ameiurus and probably not for any other fish. Regarding 
