PRELIMINARY NOTES ON THE CRANIAL NERVES 

 OF CRYPTOBRANCHUS ALLEGHANIENSIS. 



J. H. McGregor, B.Sc, 



University Fellmu in Biology, Columbia University. 



The present communication is by no means a complete 

 description of the cranial nerves of Cryptobranchus, but is merely 

 a somewhat cursory sketch of the distribution of most of the 

 more important rami. It was the hope of the writer to have 

 completed before this time a study of the brain and cranial 

 nerves of this amphibian, working out the nerve components 

 from serial sections, but the difficulty in obtaining embryonic 

 material for sectioning has so delayed the work that it has been 

 thought best to present a brief preliminary account based almost 

 entirely upon dissections of adult animals. 



Recent researches on cranial nerve components render it 

 possible to determine, even by dissection, some points of im- 

 portance in nerve homologies, though, of course, reconstruction 

 from sections will be necessary to ascertain the more intimate re- 

 lations of the components. 



In general, no attempt has been made in the present paper 

 to trace the relations between nerve-roots and the ultimate rami. 

 So far as possible the writer has endeavored to indicate homol- 

 ogies with other amphibians, basing the comparisons mainly 

 upon recent investigations on Rana, Amblystoma and 

 Salamandra. 



Netvus olfactoriiis. — This nerve is somewhat peculiar in 

 Cryptobranchus from the fact that it divides into numerous 

 branches before leaving the cranial cavity. Within the cranium 

 these branches extend cephalad in two large bundles on each» 

 side, giving each olfactory nerve the appearance of being 

 double. 



