Green, Chorda Tympa?n in Selachians. 



419 



on the inner face of the mandible, though some may also go out 

 on the hyoid. 



Fig. J. Dissection of the trigemino-facial roots of the right side of the 

 smooth dog shark, Galeus canis, seen from above. X 2. c, c, c, general cuta- 

 neous twigs for the skin of the caudal border of the orbit, com. VII, com- 

 munis fibers from the geniculate ganglion to the hyomandibular trunk, cut. 

 VII, general cutaneous fibers from the trigeminus to enter the hyomandibular 

 trunk, displaced outward during the dissection so as to expose the geniculate 

 ganglion. 



These relations correspond to those of Squalus acanthias 

 save that we have not succeeded in following the nerve regarded 

 as the chorda so far downward as to reach the ventral median 

 line. Its proximal connections could not be made out, as the 

 several ganglia of the V + VII complex cannot be clearly 

 separated by gross methods in Carcharias. Their origin from 

 the base of the palatine, which is known to be a communis 

 nerve, would, however, strongly indicate that they too are 

 communis nerves. 



