174 Journal of Comparative Neurology. 



certain, that fibers innervating end-buds scattered over the sur- 

 face of the head and even the body of the Teleosts have their 

 central termination in the lobus vagi. Such end-buds are of 

 course ectodermal. The association of such fibers with visceral 

 fibers is puzzling in any case and it has occurred to the writer 

 of this review — as well as to C. Judson Herrick — that it 

 might be accounted for on the supposition that the end-bud 

 organs originated on or near endotermal surfaces. Such a sup- 

 position is, of course, merely speculative and unless it could be 

 established, the fact that fibers innervating end-buds on ecto- 

 dermal surfaces have their central termination in the lobus vagi 

 would appear to constitute a fatal objection to Johnston's gen- 

 eralization that there are two distinct sensory systems — ectoder- 

 mal and entodermal. The partial confusion of centers for the 

 V-VIII-lateral line group which Johnston describes and which 

 led him to group these nerves together, merits a careful consid- 

 eration, however, by those who are attempting the analysis of 

 the cranial nerves in fishes. 



Johnston also comes to the conclusion that there appears 

 to be "no structure in the cord with which the lobus vagi can 

 be considered homologous." Consequently such nerves are not 

 available in determining segments of the head homodynamous 

 with trunk segments. He finally concludes that in using the 

 cranial nerves to determine segmentation, it is probably best to 

 disregard the sensory nerves altogether and use only the motor 

 series. 



The fibers of Meynert's bundle are traced beyond the gan- 

 glion interpedunculare. Most of the coarse fibers after decus- 

 sating ventral to the ansiform commissure turn dorsad, pierce 

 the above commissure and terminate in cells near the fasciculus 

 longitudinalis posterior whose neurites cross the middle line in 

 the ansiform commissure and join the ventro-lateral tracts. The 

 fine fibers could not be traced with certainty, but there is reason 

 to believe they terminate in a nucleus of small cells on the lat- 

 eral surface of the lobus linea; lateralis. 



