144 MR. F. J. COLE ON THE STEUCTURE AND MORPHOLOGY OF 



We may hence classify a typical bi-anchial nerve as follows : — 



I have already here and there referred to the facial nerve of man and mammals, 

 the morphology of which may be treated of here. In my Chimcera paper I pointed out 

 (46, p. 6C0) that the general anatomy of the facial nerve in man was in close agreement 

 with the same nerve in the lower vertebrates. A more careful enquiry into the facts 

 confirms this somewhat remarkable conclusion even in many of the details. 



The facial nerve of man and mammals may be divided into two parts, which may be 

 held to correspond to the same parts in the branchial facial nerve of fishes. These parts 

 are (1) a pre-branchial part, largely or in part visceral sensory, =the nervus intermedins 

 or pars or portio intermedia of Wrisberg, comprising the geniculate ganglion, great 

 superficial petrosal (palatine), and chorda tympani (prae-branchial) ; and (2) a post- 

 branchial part, comprising the main trunk of the facial, and being at least partly a 

 visceral motor nerve *. The points of agreement between the facial nerve of the fish 

 and mammal are as follows : — 



(1) In central origin. It is probable that the fibres of the nervus intermedins arise from 



the funiculus solitarius, which is a centre of visceral sensory fibres, and which, as 

 Strong has shown, corresponds precisely to the origin of the fasciculus communis 

 of fishes and amphibia. 



(2) In the nature of the fibres. The fibres of the nervtis intermedins are " very small," 



and hence correspond to the fasciculus communis fibres. Further, they are 

 mainly visceral sensory in function, and are certainly continued in part into the 

 chorda tympani, and perhaps also into the great superficial petrosal. The visceral 

 motor fibres of the facial trimk are represented at least by the fibres supplying 

 the stapedius muscle and those muscles of the " hyoid " develojied in connection 

 with the second visceral arch. 



(3) The geniculate ganglion is a stationary ganglion mainly in connection with visceral 



sensory fibres of the nervus intermedins. It hence corresponds to the facial ganglion 

 of the Cod and to the pre-spiracular or palatine ganglion of Elasmobranch fishes. 



* See Wiedersheim (lt^97, 221), where the relations of these nerves are well shown (p. 183), 



