52 Bulletin of Laboratones of Denison University, [voi.xiii 



exceedingly fine branchlets among which the arborizations of 

 the root fibers end. From one or more of the terminal branches 

 of this dendrite a very delicate neurite arises and goes by the 

 shortest path directly into the layer of secondary tracts by 

 which it leaves the vagal lobe to enter the longitudinal second- 

 ary gustatory tracts of the oblongata, meanwhile taking up a 



Fig. g. A chief secondary gustatory neurone from the vagal lobe of the 

 carp — the neurone designated a on Fig. 8. X 250. The black mass at the left 

 of the neurone is precipitate deposited in the external limitating membrane of 

 the vagal lobe. 



very delicate medullary sheath. In its passage through the 

 layer of secondary tracts it sometimes gives collaterals into the 

 motor layer of the vagal lobe (Fig. 10). 



Upon casual examination these chief neurones might sug- 

 gest the appearance of neuroglia elements. The latter, how- 

 ever, are of totally different form (Fig. 6) and there is no oppor- 

 tunity for confusion. The gustatory neurones have exceedingly 

 fine and densely branched dendrites, while the branches of the 

 neuroglia are thicker and of the peculiar mossy or pulverulent 

 appearance so characteristic of the supporting elements. The 

 neuroglia, moreover, as a rule impregnates with a dark brown 

 instead of black color. 



Besides the chief gustatory neurones just described, there 

 are closely associated with them just internally the smaller gus- 

 tatory neurones shown in Figs. 11 and 12. These have the 

 same general form and arrangement, but are much simpler. 

 The cell body is smaller and usually rounded and the dendrite 

 less profusely branched. The slender neurite arises from the 

 tip of the dendrite and enters the layer of secondary tracts. 



