l62 NERVE COMPONENTS OF BONY FISHES. 



from the anterior two-thirds of the tongue by means 

 of the lingual nerve (V+VII), rather than by the IX 

 nerve. Clinical evidence is then adduced to show that 

 these gustatory fibres enter the brain through the V nerve 

 rather than the VII, which, however, does not seem to me 

 by any means conclusive. 



A pre-facial fasciculus solitarius has been described in 

 man by a few writers (Bottiger, '90, and Roller, '81). 

 Only upon the supposition that such a tract does enter 

 the trigeminus (a condition which has not been demon- 

 strated as yet in any of the lower animals) could the 

 presence of gustatory fibres in the trigeminus roots be 

 explained. In the present state of our knowledge we may 

 most safely consider that Dixon's conclusion in man 

 applies to all of the vertebrates: " The nerve supply of 

 the organs of taste appears to be derived from the facial 

 and glossopharyngeal nerves alone." 



In man, then, so far as is definitely known, the pre- 

 auditory communis system is represented by the large 

 superficial petrosal nerve and the chorda tympani, plus a 

 few fibres in the facial proper — see the reference to Van 

 Gehuchten above. Since the days of Stannius the large 

 superficial petrosal is pretty generally regarded as the 

 homologue of the r. palatinus. The homologies of the 

 chorda tympani, however, have given more trouble. In 

 determining this question there are three criteria or lines 

 of evidence which have been very differently estimated 

 by different authors: (i) The character of the fibres, 

 their ganglion and central termination, (2) the peripheral 

 distribution area, (3) the intermediate course of the nerve, 

 especially with reference to the spiracle and its limiting 

 arches. 



Froriep's comparison ('87) with a lateral line nerve of 



