656 MR FRANK J. COLE ON THE 



belong to and come from the facial proper ; (c) a conspicuous nerve passes through the 

 ampulla?, and, dipping down in the direction of the pharynx and then running backwards, 

 ends in a small but totally distinct and very compact group of ampullae lying at the 

 angle of the mouth between the lower lip and the mandible (see fig. 1). 



It will thus be seen that there are three kinds of ampullae in Chimsera, which are — 

 (1) large compound, as in superficial ophthalmic and inner buccal groups; (2) small 

 compound, as in outer buccal group ; (3) simple and kidney-shaped, as in mandibular 

 group. The latter are the smallest of the three. 



(4) Lateralis. — The lateralis arises somewhat in front of and on a slightly higher 

 level than the roots of the vagus, and partly in front of the roots of the glosso-pharyngeal. 

 The posterior rootlets of the lateralis more or less completely obscure the roots of the 

 vagus, but dissection readily shows that the lateralis is quite independent of the vagus. 

 Whilst still in the cranium, the lateralis gives off a dorsal twig, which, uniting with 

 another given off from the ganglion, forms the large dorsal branch to the occipital 

 portion of the lateralis canal. The origin of this nerve is somewhat deceptive, since it 

 seems to arise partly from the 2nd and 3rd branchial ganglia, and requires careful 

 dissection.* The dorsal branch courses straight upwards and gives off eight twigs, which 

 supply the first 9 sense organs of the lateralis canal. The median dorsal portion, or 

 ' post-aural ' of Garman, was supplied from the right side. The lateralis runs sharply 

 backwards, and, after passing through the vagus foramen, immediately expands into the 

 large lateralis ganglion. The nerve then courses backwards, roughly parallel to the 

 lateralis canal, and innervating it for the whole of its length. 



(5) Auditory Nerve. — It has long been known that the auditory nerve can no longer 

 be considered an eighth cranial nerve, and it also seems to be generally admitted that 

 the auditory organ is an extremely modified portion of the lateral line system. t I there- 

 fore venture to describe it here. The auditory nerve arises by a stout root from the 

 lateral lobes of the medulla in the triangular space inclosed by the ventral root of the 

 superficial ophthalmic and the root of the buccal. It very soon expands into the large 

 auditory ganglion, and gives off a longish nerve to the posterior ampulla. The latter, 

 just at its origin, gives off a very short thick nerve to the sacculus, which contains an 

 hitherto undescribed curiously shaped hard otolith (see figs. 4 and 5). Further on, the 

 thickest of the divisions of the auditory nerve arises, which soon divides into a stout 

 nerve to the external ampulla, and another thinner one to the anterior ampulla. The 

 auditory nerve of Chimsera thus apparently corresponds to that of Lsemargus. 



Literature. — Stannius makes very few references to the facial of Chimsera in his text. 

 He figures my post-branchial C, or the major part of what he calls the ' ramus opercularis,' 

 and describes it (p. 61) as supplying the constrictor of the ' Kiemenhohle.' He seems 



* Further complications are the dorsal branches of the cranial spinals (see fig. 2). 

 t Cp. particularly Ayers (Jour. Morph., vol. vi., 1892) and Strong (68). 



