26 Journal of Comparative Neurology. 



the comparison of spinal and cranial nerves. Strong's conclu- 

 sions as to the components of the cranial nerves of Ichthyop- 

 sida may perhaps be best given in his own words : "We have 

 seen that in the cranial nerves of the higher fishes there are 

 three kinds of cutaneous nerves distinguishable by peculiarities 

 of their fibers, of their distribution, and of their internal ori- 

 gin, i. e., (i) mixed fibers of a general cutaneous character 

 continuous with the posterior columns of the cord, (2) coarse 

 fibers innervating the lateral line organs and terminating cen- 

 trally in the differentiated tuberculum acusticum, and (3) fine 

 fibers innervating the terminal buds ( coarse in Selachians and 

 innervating the ampullae ? ) and terminating centrally ( princi- 

 pally) in the lobus trigemini. The latter, /. e., (3), is possibly 

 not completely differentiatiated. Among the Cyclostcmes, it 

 seems probable that this specialization has not been carried so 

 far, but this is not yet sufficiently known. " In addition and disre- 

 garding here the motor ( rfon-ganglionated ) components was 

 recognized the fasciculus coimnunis component, composed of 

 fine myelinic or amyelinic fibers which constitute the ( visceral ) 

 nerves of the alimentary tract. Speaking of its great develop- 

 ment in fishes, he says : "Its great development in fishes is 

 correlated with the development of the gills, and where these 

 are in process of reduction or lost it is correspondingly re- 

 duced " (p. 190). Thus then in addition to the motor nerves, 

 there exist in the cranial nerves, components as follows : — (a) 

 general cutaneous, (b) lateral line, (c) end-bud, and (d) splanch- 

 nic ; and these having their central connections in or through 

 (a) the ascending V (spinal V tract), (b) tuberculum acusti- 

 cum, (c) lobus trigemini and (d) lobus vagi — fasciculus com- 

 munis. 



In regard to the relation of the last two regions, the ac- 

 counts of different writers introduced difficulties that prevented 

 conclusions at all definite being reached. The difficulty, upon 

 a study of the oblongata, shows itself to be due largely to the 

 careless application of the same term in teleosts and elasmo- 

 branchs to structures which are not homologous, and for this 

 obscuration both Goronowitsch and Mayser appear in a degree 



