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Show 278 ME. W. E. COLLINGE ON THE [Apr* 2, region the nerve divides into two branches, each of these again dividing into numerous fine twigs. 2. The ramus buccalis supplies all the sense-organs of the suborbital branch. It branches from the Gasserian ganglion above the ramus maxillo-mandibularis, to which it is connected by a fine branch. It passes forwards, crossing the floor of the orbit, and terminates in a series of fine branches. In its course forwards it gives off a series of fine branches which supply the sense-organs between the pores 10 to 15. 3. The ramus oticus innervates the greater portion of the main canal and the backwardly directed branch of the supra-orbital branch which terminates at pore number 9 (fig. 1). The ramus oticus passes above the facial (PI. XVIII. fig. 1, r.ot.) and divides into two branches; the main branch passes backwards along the main canal and the other makes a lateral curve forwards and supplies the small branch which is given off from the supra-orbital branch and terminates at pore 9. The Facial Nerve.-The only branch entering into connection with the sensory canal system is the ramus mandibularis. This nerve arises as a branch of the ramus hyomandibularis. The latter nerve traverses a canal in the hyomandibular bone, some little distance below which it divides into two; the ramus hyoideus passing ventrally and the ramus mandibularis forwards, giving off numerous branches to the mandibular portion of the operculo-mandibular branch of the sensory canal. The Glossopharyngeal Nerve in C. magur does not run or arise in conjunction with the vagus, as Pollard (11. t. 35. fig. 1) has figured in Clarias, sp. In all the specimens examined I find it arises slightly dorsal to, and quite distinct from, the vagus. Its anterior branch passes dorsally, and the posterior one to the posterior portion of the main canal of the head. The Vagus.-The ramus lateralis vagi passes off from the vagus as a lateral division. It sends off a short branch which passes to the commencement of the main canal; it then proceeds outwards and backwards, giving off a series of fine branches, which pass between the muscles and supply the sense-organs in the anterior region of the lateral canal. 2. AMIUEUS CATUS. General Description. The sensory canal system of this fish has been briefly described by Ramsay "Wright (12) and is also referred to by Allis (1). Very briefly I will give a summary of the observations of these two writers in order that I may not have to point out at any length the differences between our respective accounts. The references made by Allis are very brief. Speaking of the operculo-mandibular canal in Amia he says (p. 473): "The mandibular and opercular portions of the canal develop as two distinct canals, uniting later with each other to form a continuous |
