The Lateral Sensory System in the Muraenidae. 147 



innervated by branches of the former nerve and organs 9 and 10 by 

 branches of the latter. The fnll conrse of these nerves will be des- 

 cribed in a later work, but it may here be said that the innervation 

 shows that organs I to 4 belong to an anterior group and organs 5 

 to 8 to a posterior group, Conger thus agreeing in this respect with 

 Amia, Scomber, Mustelus and other fishes (No. 7, p. 124). 



In addition to these ten infraorbital organs there are two lateral 

 canal organs, on each side of the head, innervated by the buccalis. 

 They lie in a canal that communicates directly, by anastomosis, with 

 the supraorbital canal, as already stated in describing the canals in 

 the other Muraenidae, and the canal, which I have called the ethmoi- 

 dal canal, has such unusual relations to the anterior end of the skull 

 that a short description of this part of the head of the fish is 

 necessary. 



On the end of the snout of Conger (figs. 17 and 18), on each 

 side of the head, and not far from the middle line, there are two 

 vertico-longitudinal creases which begin on the under, ventral surface 

 of the upper lip and run upward and backward, cutting into the lip 

 and into the end of the snout and gradually vanishing as they ap- 

 proach the top of the snout. The creases cut laterally and back- 

 ward into the end of the snout, and two vertical dermal folds, or 

 lips, are thus formed which enclose between them a rounded ridge 

 which forms a median slightly projecting and beak-like part of the 

 end of the snout. This median ridge has no evident relations to the 

 underlying parts of the skull. The two lateral folds, one on each 

 side of the ridge, lie, on the contrary, almost directly external to the 

 ethmoidal canal and suggest in a way the V-shaped ethmoid bone of 

 Amia. The outline of the end of the snout of Conger also resembles 

 in a striking Avay the outline of the end of the skull of Scomber 

 (No. 9), though what the relationships here could be is not evident 

 Each of the two folds of Conger bears, on its summit, a vertical line 

 of relatively large surface sense organs. A line of apparently similar 

 but somewhat larger surface organs, on each side, encircles the ven- 

 tral edge of the base of the nasal tube. 



The ethmoidal canal begins, on each side, at a pore that lies 



ventro-mesial to the nasal tube, close to the ventral edge of the upper 



10* 



