CoGHiLL, Cranial Nen>es of Ainblystouia. 263 



alveolaris VII. In Spelerpes, also, the second and third 

 cutaneous branches of the mandibularis V of Amblystoma are 

 represented by a single nerve. 



The two accessory trigeminal twigs which I have described 

 as occurring sometimes in Amblystoma seem not to have been 

 noticed in other Urodela. They may correspond in an indefi- 

 nite manner to the two inner " accessory " trigeminal rrimi of 

 the tadpole as described by Strong ; but they are so variable 

 in their occurrence that their morphological value cannot be 

 determined without microscopical study of a large series of 

 specimens. 



^. — The Lateralis Coniponefit of the Facialis. 



The t. hyomandibularis proper scarcely extends beyond 

 the lateral border of the ear capsule in Amblystoma. It agrees 

 in this regard with the same trunk in Spelerpes (Bowers), 

 Salamandra, Triton, Necturus and Proteus (Druner, '01). In 

 Anura the trunk extends to the region of the angle of the jaw 

 as it does in many fishes. The composition of this trunk in all 

 Amphibia, so far as they have been adequately studied,, is 

 lateralis, motor and communis. In no case have any of its 

 neurones been found to enter the tractus spinalis n. trigemini. 

 The assignment of a general cutaneous function to certain of 

 its rami will be noticed in a following paragraph. 



The nomenclature of the lateralis component of this trunk 

 in Amphibia is unfortunately mixed. I have employed the 

 "mentalis" of earlier authors to include the entire laterahs 

 component of the trunk. Excepting the erroneous application 

 of this term to the r. mandibularis internus of Anura by cer- 

 tain earlier authors (Hoffm.\nn, '78), " mentalis " has been 

 most used in the anatomy of Urodela. In treating Spelerpes 

 Bowers has used Strong's terminology for the tadpole, " man- 

 dibularis e.xternus," without limitations. This usage is prob- 

 ably in a general way correct, in the light of Kingsbury's ('95) 

 work on the lateral line system of Amphibia. But owing to 

 important differences in regard to the other rami of the 

 hyomandibular trunk of Urodela on the one hand and Anura 



