412 journal of Comparative Neurology and Psychology. 



developed, as a rule, as is also the funiculus dorsalis, no distinc- 

 tion into fasciculus gracilis and fasciculus cuneatus being possible. 

 The only neurones of the dorsal cornu which are often impregnated 

 in my preparations are small cells whose neurites reach the for- 

 matio reticularis of the same side (Fig. 8). 



Laterally of the cornu dorsalis there is a large fascicle of heavily 

 medullated fibers which is usually apparent to the naked eye as a 

 strand on the dorso-lateral aspect of the spinal cord and which is 

 separated from the more ventral masses of the funiculus lateralis 

 by a fissure or groove. This, I shall term the fasciculus dorso- 

 lateralis (Figs, i to 6, /. d. /.). It includes the spinal residue of the 

 spinal V and descending secondary VII tracts and ventrally of 

 these a much larger number of long fibers, most of which pass 

 cephalad from the spinal cord to end in the region of the funicular 

 nuclei and farther forward into the medulla oblongata. It does 

 not receive dorsal root fibers of the spinal nerves. These enter the 

 funiculus dorsalis (Figs. I and 2). The impression given by my 

 preparations is that the dorso-lateral fasciculus is composed w^hoUy 

 of ascending fibers, save for the descending trigeminus and secon- 

 dary facialis tracts just mentioned. On the other hand, the 

 remainder of the funiculus lateralis (marked /. /. on the figures) 

 seem to be composed chiefly of descending fibers.^ There is a 

 broad band of unmedullated external arcuate fibers between the 

 cephalic end of the funicular nucleus and the visceral commis- 

 sural nucleus jabove and the ventral funiculi below. This con- 

 nection is especially well developed in cyprinoids. 



In the dorso-lateral fasciculus the following distinct elements 

 may be recognized : 



1. The greater portion terminates in the median funicular nu- 

 cleus (ascending fibers. Figs. 3, 4, 9, 13 and 14). 



2. Another division of ascending fibers ends in the lateral funic- 

 ular nucleus (Figs. 4, 5 and 13). 



3. Another part consists of the spinal V tract, descending fibers 

 which terminate in the nucleus of the spinal V tract and farther 

 caudad in the spinal cord (Figs. 3, 4, 7, 13 and 14). , 



lit should be stated, however, that my preparations do not give positive proof that the latter fibers run 

 in the direction indicated. I mention this here because it is my rule in these papers to make no unquali- 

 fied statements regarding the direction taken by a fiber tract without observational evidence. That the 

 dorso-lateral fibers are chiefly ascending I can assert positively from their mode of ending in the funicular 

 nuclei as shown by Golgi preparations. 



