Herrick, Medulla Oblongata of Fishes. 4I I 



described. It and its commissure are intimately related to the 

 funicular nuclei and will be more fully discussed in a later article. 



Passing forward to the vagal lobe, we find here a second enlarge- 

 ment of the general visceral sensory component correlated with the 

 increase of mucous surface in the gill region, and in addition, an 

 extreme differentiation to provide the terminal nucleus of the fibers 

 from the numerous taste buds found in that same mucous mem- 

 brane. Still farther cephalad we have in Ameiurus a similar and 

 more recently acquired specialized derivative, the facial lobe, to 

 receive the fibers from the taste buds of the outer skin. 



Both the facial and the vagal lobes give rise to long ascending 

 secondary tracts in addition to the short reflex paths just described. 

 These terminate in the superior secondary gustatory nucleus under 

 the cerebellum (nucleus lateralis cerebelli) and will not be further 

 considered in this paper (c/. Herrick, '05). There are, moreover, 

 long descending secondary gustatory tracts, to whose considera- 

 tion, we must next turn. Those from the vagal lobe and commis- 

 sural nucleus are not well defined and can scarcely be distinguished 

 from the short paths to the formatio reticularis. They are prob- 

 ably of the same tpye, i. e.y chiefly visceral and gustatory reflex 

 paths for the visceral musculature. The descending secondary 

 tract from the facial lobe, however, is large, compact and heavily 

 medullated. Its origin from the cephalic part of the facial lobe 

 and its position dorsal to the ascending secondary tract suggest 

 that it has been differentiated in the course of the phylogeny more 

 recently than any of the other secondary gustatory tracts. It passes 

 back ventral to the spinal V tract and closely joined to it and before 

 the level of the funicular nuclei is reached has been enveloped 

 ventrally by the cephalic part of the dorso-lateral funiculus to be 

 described later. It is in fact a part of that funiculus and its further 

 course cannot be described apart from that fiber complex and its 

 associated gray centers. We shall, therefore, next give an account 

 of the somatic sensory centers of the spinal cord and lower part 

 of the oblongata. 



The caudal end of the medulla oblongata and the cephalic end 

 of the spinal cord are dominated by the somatic sensory centers in 

 nearly all teleosts. There are two well defined gray centers, as in 

 the mammals, the funicular nucleus and the nucleus of the spinal 

 V tract, whose development varies greatly in different species. 



In the lower levels of the spinal cord the cornu dorsalis is feebly 



