Herrick, Tactile Centers of Priotiotus. 313 



ascending correlation fibers of the tactile system, since this tract 

 is larger in this fish than in any other which I have examined and 

 there is no enlarged structure in the oblongata from which its 

 fibers may arise. There are also added to the ventral side of the 

 ventro-lateral fasciculus large heavily medullated tracts which 

 arise from the funicular nucleus and pass cephalad into the oblon- 

 gata. These are believed to be in the main ascending correlation 

 tracts for the same reason as those last mentioned. Some of these 

 tracts enter the dorso-lateral fasciculus by way of the adjacent 

 formatio reticularis. 



Probably there are important descending secondary tracts from 

 the funicular nucleus in the lateral and dorso-lateral fasciculi, but 

 they are not separately distinguishable. Contrary to my expecta- 

 tions, neither the funicular nucleus nor any of the accessory lobes 

 send large secondary tracts to -the ventral funiculi. The very 

 large internal arcuate tracts from the funicular nucleus nearly all 

 terminate in the ventral cornu immediately adjacent. Nor do any 

 large numbers of these secondary fibers ascend in the fasciculus 

 lateralis (of Mayser, "lemniscus," Herrick), as was to have 

 been expected by analog)' w^ith other fishes. In short, the enlarge- 

 ments represented in the accessory lobes represent a sensori-motor 

 mechanism for the free rays of the pectoral fins, and these modifi- 

 cations do not extend far beyond the limits of the segments of the 

 spinal cord directly involved in the innervation of these fins. The 

 modifications of the spinal cord behind the "lobes" is more evident 

 than that of the medulla oblongata in front of them. This doubt- 

 less is correlated with the fact that the sensory stimulation of the 

 free rays is more apt to call forth swimming movements of the 

 trunk and tail musculature than any cephalic reaction. The 

 specialized apparatus of these free rays, then, is adapted for 

 reflexes of only the simplest order. 



A study of the series of excellent figures of Lophius given by 

 Kappers ('06) reveals in the funicular nucleus region an arrange- 

 ment very similar to that of Prionotus. The somatic sensory 

 centers are much enlarged and are designated nucleus Rolandi and, 

 farther caudad, lobus sensib. Probably these masses of grey 

 include both my funicular nuclei and the spinal V nucleus. The 

 commissura infima is no doubt chiefly somatic, the visceral centers 

 being small in this fish. 



The accessory lobes, as we have already seen, are enlarged 



