CoGHiLL, Cranial Nenies of Amblystoma. 273 



constant arrangement which can be compared with that of 

 Necturus. 



2. — The Lateral Lme Component. 



The r. supratemporalis of Amblystoma corresponds to 

 the nerve of that name described by Strong for the tadpole of 

 the frog. Here as in Amblystoma it arises as a distinct nerve 

 from the ganglion and is a purely lateral line nerve. The nerve 

 which Bowers calls R. supratemporalis in Spelerpes arises from 

 the ganglion in union with the r. auricularis and separates from 

 the latter soon atter leaving the ganglion. This nerve, accord- 

 ing to Bowers' descriptions and figures, cannot represent the r. 

 supratemporalis of Amblystoma, but is a part of the r. 

 auricularis which is both lateralis and general cutaneous. 



According to Druner's researches, the r. supratemporalis 

 is probably absent in Triton, Salamandra and Proteus, In 

 Menobranchus, however, this author describes a small nerve 

 which arises independently from the ganghon and sends fibers 

 to the skin. He describes it, also, as innervating the first m. 

 levator arcus branchii (p. 609). This nerve, I believe, is the r. 

 supratemporalis. As described in Part First of this paper, one 

 division of this nerve may penetrate the m. levator arcus 

 branchii. There is no evidence, however, of any of its fibers 

 terminating in the muscle. Moreover, the nerve is derived 

 from the lateralis root, which contains no motor fibers. In 

 failing to trace this small division of the nerve through the 

 muscle, no doubt, Druner has been led to interpret it as 

 motor. 



The r. auricularis vagi of Amblystoma is in part a lateral 

 line nerve. In the tadpole (Strong) and in Spelerpes (Bowers) 

 it is purely general cutaneous. However, as suggested in the 

 above paragraph, the nerve which Bowers interprets as lateral 

 line in function is in all probability a branch of the r. auricu- 

 laris. This entire nerve appears essentially in the same rela- 

 tions in Salamandra, Triton, Proteus and Menobranchus, and 

 Dritner recognizes in these forms also that it contains fibers to 

 the lateral line sense organs. It seems certain, therefore, that 



