658 MR FRANK J. COLE ON THE 



tinguished from the prae-spiracular, the former being equivalent to the post-branchial 

 division of the Vllth. Jackson and Clarke (16) describe prse-spiracular nerves from 

 the palatine, and a post-branchial internal mandibular or chorda tympani. Froriep's 

 mistake (40) has been pointed out too often to be specially mentioned here, but I agree 

 with Strong that Froriep possibly had the right nerve, but gave it the wrong name 

 (i.e., called the mand. int. the mand. ext.). Froriep further criticises Balfour's view 

 above. Ewart (57) describes the ' palato-facial ' or facial proper as follows (I ven- 

 ture to reproduce his description, on account of its having been published in a some- 

 what inaccessible form) : — " The palato-facial arises immediately in front of the auditory 

 by a single root, and as it proceeds outwards it receives a small bundle of fibres from 

 the auditory (the pars intermedia). Having escaped from the cranial wall it expands and 

 divides into the palatine and facial trunks. The facial trunk, which contains numerous 

 ganglionic cells, on leaving the palatine sends several small branches in front of the 

 spiracle (pre-spiracular branches) and a branch which passes backwards external to the 

 auditory capsule. This branch supplies the muscle lying between the auditory capsule 

 and the hyomandibular cartilage, and extends as far as the anterior wall of the hyoid 

 gill. It probably represents the posterior auricular branch of the facial of mammals. 

 The main trunk of the facial proceeds outwards in intimate relation with the hyoman- 

 dibular nerve to near the outer end of the hyomandibular cartilage. The several 

 bundles of the facial then bend sharply round the hyomandibular cartilage, and come 

 into close contact with the anterior wall of the hyoid gill. Some of the fibres are 

 distributed to the hyoid gill, and others reach and end in the jaw muscles, whilst the 

 remainder proceed to the mucous membrane lying in the hyoid region, i.e., to the part 

 of the floor of the mouth lying between the mandible and the hyoid, or, in the absence 

 of the hyoid, the first branchial arch. These last-mentioned fibres I look upon as 

 representing the chorda tympani of the mammal." It is evident that Ewart's chorda 

 tympani = the mandibularis internus of Stannius and Jackson and Clarke. Strong 

 (61 and 68) also homologises the chorda tympani with a mandibularis internus, but 

 further confuses matters by identifying what is clearly the prse-spiracular nerve as the 

 internal mandibular. My reasons for this assertion are two : (l) his mand. int. arises 

 from, the base of the palatine, which is almost invariably the origin of the prae-spiracular 

 nerve ; # (2) it consists entirely (?) of splanchnic sensory fibres (and thus agrees with the 

 palatine), whereas the post-branchial division of the Vllth is practically motor. Strong 

 was apparently misled by the fact that the prse-spiracular of his amphibia (Frog and 

 Amblystoma), after its origin from the palatine, accompanied the post-branchial division 

 of the Vllth. I therefore agree with Strong's homology, but would substitute the 

 word ' prae-spiracular ' for ' internal mandibular.' Gaupp (Schwalbe's Morph. Arb., Bd. 

 ii.) and Pollard (Zool. Jahr., Bd. v.) also considered that the chorda of mammals was 



* This assertion, minus the 'almost,' is made upon the reliable authority of Stannics. The prae-spiracular is 

 wrongly figured by Marshall and Hurst, but rightly by Stannius for Acanthias (Plate II. fig. 1). Cp. further the 

 description of the IXth of Mustelus given by Ramsay Wright (34). 



