978 [ynis. o. a. merritt hawkes on the [Dec. 11, 



of the same diameter, wliicli stained in the same way. As it is 

 certain that the dorsal bi-anch of the Vagus supplies neuromasts, 

 these large fibres are no doubt lateralis fibi-es in the doi'sal branches 

 of both the Glossopharyngeus and Vagus. On histological grounds, 

 therefore, the innervation of neuromasts by a dorsal branch of the 

 Glossopharyngeus may be considered certain. Both dorsal branches, 

 especially that of the Vagus, contained smaller medullated fibres, 

 probably general cutaneous. The next following neuromast was 

 supplied by the lateralis vagi. The position of these two neuro- 

 masts, which are supplied by this dorsal branch of the ninth nerve, 

 are in appi'oximately the same position as those innervated by the 

 ninth nerve in some Siluroids. It should be noticed that inAviia 

 the dorsal branch of the ninth nerve had a separate root and 

 ganglion, and that this dorsal branch must be regarded as a part 

 of the lateral-line system (3. p. 666). The portion of the nerve 

 which it was not possible to ti-ace probably supplied the dorsal 

 cutaneous area, and partly represented the general cutaneous 

 elements of a dorsal ramus. Cole (3. p. 664), speaking of the 

 condition in Chimcera, gives no explanation of this dorsal branch, 

 but merely says : "a dorsal branch .... passes straight up to the 

 skin of the occipital region." In species in which there is no lateralis 

 dorsal branch on the ninth nerve, these neuromasts are doubtless 

 innervated by the r. lateralis vagi. A similar dorsal branch of 

 the Glossophaiyngeus is described by Ewart and Cole (6. p. 476) for 

 Lcemargus, which divided into two branches, one supplying neuro- 

 masts (three), and the caudad, which was not traced in Chlcvmydo- 

 selachus, supplying " fibrous tissue between the muscles and the 

 cranium." 



From the inner side of the glossopharyngeal ganglion a fine 

 nerve passes outwai-ds above the space between the \ryo\d and the 

 first branchial arches, and next bends suddenly downwards a,nd 

 inwards towards the roof of the mouth. It there divides into 

 three branches, which pass forward along the roof of the pharynx, 

 parallel and equal. In this group of branches we find the 

 equivalent of the single visceral branch of other species. 



The pre-trematic IX. passes along the inner side of the hyoid 

 arch, contiguous with the efferent branchial blood-vessel. About 

 6 cm. from its origin the nerve divides into a number of small 

 branches which appear to be distributed throughout the arch. 

 These branches cannot be followed to their terminations, but are 

 probably wholly sensory. 



The post-trematic IX. is lai-ger than the pre-trematic. It passes 

 along the inner edge of the first branchial arch, sending many 

 small branches into the filaments and two branches over the 

 cerato-branchial cartilage at the outer angle of the arch. The 

 main portion of the nerve terminates ventrally on the pharynx in 

 a number of fine branches. 



On the right side of one specimen the glossopharyngeal ganglion 

 and a small portion of the post-trematic IX. were bound by 

 connective -tissue to the Vagus. The glossopharyngeal ganglion 



