292 . ME. W. B. COLLIKGE ON THB [-^V^- 2, 



the actual distribution is the same ; in fact they are a feeble fac- 

 simile of the more superficial complete canals. 



I have already described how the occipital commissure passes off 

 from the point of junction of the lateral canal and the main canal 

 of the head. At this point a branch passes downwards into the 

 substance of the parietal and frontal bones (PI. XX. fig. 14) and 

 in a lateral direction towards the border of the frontal bone, where 

 it divides into three branches — a backwardly directed one to the 

 region of the preoperculum, a forward and laterally directed one 

 (a sub-orbital branch), and a forward one, which passes inwards for 

 some distance, making an outward curve and passing through the 

 supraethmoid (Parker) and terminating blindly in the nasal. 

 Sometimes it passes only as far as the supraethmoid (Parker). In 

 some cases it was very difficult to decide whether the branch 

 leading to the preoperculum was present. In a very large speci- 

 men I thought there were indications of a small branch passing 

 between the head of the preoperculum and the supra-orbital bone. 

 Although connected with the more superficial system, none of 

 these canals are functional. 



VI. MUB^NIDiE. 



Congee congee. 

 General Description. 



The sensory canal system has not hitherto been worked out in 

 the Conger. Arsaky (1836) has investigated the central nervous 

 system, but I have been nnable to refer to his work. 



The lateral canal commences about 18 millim. from the tip of 

 the tail and passes forwards in the integument. The pores distri- 

 buted over its surface and opening into the canal are numerous. 

 In the anterior region it passes sUghtly dorsally and enters upon 

 the region of the head, terminating by opening into a wide 

 saccular dilatation from which the occipital commissure arises, also 

 the main canal of the head and the operculo-mandibular branch. 

 The main canal passes through the frontal and divides into the 

 supra- and sub-orbital branches, the former passing along the orbit, 

 and terminating by a large pore in the most anterior portion of the 

 face ; the sub-orbital passes behind and beneath the orbit, terminating 

 beneath the opening of the supra-orbital branch. In its course 

 three large saccular dilatations are given off, the first of which 

 opens by a large pore. The operculo-mandibular branch commences 

 at the termination of the lateral canal. It gives ofE a saccular 

 dilatation at its commencement and again at the base of the 

 opercular portion, and a third slightly in front of this ; it then 

 passes forwards along the mandible, opening in its course by four 

 pores, and meets with its fellow of the opposite side. 



Course of the Canals and Branches. 

 1. The Lateeal Canal passes in the integument from the 

 posterior end of the body, 16 miUim. from the end of the trunk, 

 exclusive of the caudal fin, to the region of the head. In the 



