No.!.] THE CRANIAL NERVES OF AMPHIBIA. 125 



to be most numerous always over the opening into the gill 

 cavity. In those parts of the roof not directly above this open- 

 ing they immediately dwindle away. 



The nerve fibres, in my preparations, form beneath the 

 epithelium a dense plexus from which fibres pass upward into 

 the epithelium. In the thinner, indifferent epithelium, which 

 seems usually to be the least richly innervated, they run among 

 the cells irregularly, but do not as a rule seem to penetrate 

 more than about two-thirds through its thickness towards the 

 surface. 



A number of nerve fibres approach the base of the taste 

 bulbs and there break up, forming a dense structure (PI. IX, 

 Figs. 15, 16, and 24), often, apparently, more of a granular than 

 fibrous character, and at times staining less black than the 

 nerve fibres. This structure evidently corresponds with that 

 described by von Lenhossek in fishes (38) and termed by him 

 the cupula. From this structure nerve fibres arise which 

 ramify around the bud, often rising nearly to its peripheral 

 surface. Whether they also penetrate between the cells of the 

 bud it is rather difficult to determine. 



The nerve fibres passing immediately below the 7milticellular 

 glands send at right angles vertical fibres up into them or close 

 around them. The course of these fibres varies somewhat. 

 In some preparatioYis they rise nearly parallel with each other 

 almost to the very surface of the epithelium where they end 

 in little knobs either among the cells of the bud or immediately 

 around them (PI. IX, Fig. 17). In other cases the fibres rise 

 more irregularly, and when they have penetrated into the upper 

 third of the epithelium they turn and branch so as to form 

 a dense ring-like plexus apparently encircling or penetrating 

 the gland at this level. From this plexus a number of nearly 

 parallel fibres pass upwards converging towards the central axis 

 of the gland and end in enlargements in or very near the 

 surface of the epithelium (PI. IX, Figs. 18 and 19). I am 

 inclined to believe that the latter fibres, at any rate, penetrate 

 into the gland near its free surface. Transitional forms are 

 abundant where the fibres from the subepithelial plexus pass 

 upward more as in the first mode of termination, but branch 



