| OCR Text |
Show 292 .: ME. W. E. COLLINGE ON T H E [Apr. 2, the actual distribution is the same ; in fact they are a feeble facsimile 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. X X . 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 specimen 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. MUE-ENIDJE. 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 unable 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 distributed over its surface and opening into the canal are numerous. In the anterior region it passes slightly 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 off 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 L A T E E A L C A N A L passes in the integument from the posterior end of the body, 16 millim. from the end of the trunk, exclusive of the caudal fin, to the region of the head. In the |
