THE CHORDA TYMPANI. 169 



trematic branches must of necessity arise " from the base 

 of the palatine," Compare especially my Fig. 4. His 

 second reason we have criticised just above. 



Strong's internal mandibular is, I am confident, the 

 same nerve as the one so named in Menidia, and I believe 

 it to be homologous with the post-spiracular mandibularis 

 internus of Amia (Allis, '97) and of some selachians 

 (Stannius, '49, p. 65, and Jackson and Clarke, '76), and 

 not completely so with the chorda of mammals. I say 

 not completely, for it may well be that the pre-trematic 

 VII in the frog has fused with the post-trematic, or hyo- 

 mandibular nerve, so that the amphibian r. mandibularis 

 internus VII may represent both the pre- and the post- 

 spiracular communis elements. 



Cole, in his admirable memoir on the nerves of the cod- 

 fish ('98a), re-states his argument on the chorda (pp. 200- 

 201). Though no new facts are brought out, yet the 

 "confusion in the terminology of the facial nerve of 

 fishes " is, I fear, rather augmented than diminished, and 

 an examination of his argument in detail is necessary. 



In the first place he says: "As. I have already pointed 

 out (1896, ^(5, p. 657 et seq.) the terms internal mandibular 

 and Jiyoideus as first used by Stannius are not only synon- 

 ymous but apply to a motor post-spiracnlar nerve related to 

 the anterior face of the hyoid arch, just as the pre-spirac- 

 ular nerve should be related to the posterior face of the 

 mandibular arch." This, I think, is hardly fair to 

 Stannius. 



In selachians Stannius describes ('49, p. 65) two 

 branches of his (post-spiracular) truncus hyoideo-mandi- 

 bularis, the r. mandibularis externus and the r. mandibu- 

 laris internus s. profundus, which have since that time 

 been very generally regarded as lateralis and visceral 

 nerves respectively, the latter distributing to the mucous 

 lining of the mouth. In his description of the teleostean 

 arrangement both of these components of the r. mandib- 



