404 DAVIDSON BLACK 



the gill arch nerves had in each case been similarly determined 

 by the influence of the communis center. However, in the case 

 of Triton, though gill respiration is lost in the adult just as 

 completely as it is in anurans, yet the motor VII-IX-X nuclei 

 are arranged in essentially the same manner in this animal as in 

 Siren. Kappers concluded that in spite of the absence of gill 

 respiration, the selachian arrangement of the motor VII-IX-X 

 nuclei in Triton was determined by the position of the visceral 

 sensory VII nucleus within the communis area, and he drew 

 further attention to the equa^l development of this area in both 

 Siren and Triton. In addition he pointed out that the VII 

 gustatory components in Siren and Triton were of greater im- 

 portance than in Rana, and considered that tjiis circumstance 

 might furnish an explanation of the strong influence of the com- 

 munis area upon the motor VII nucleus in urodeles. 



In comparison with ganoids and teleosts, the number of taste 

 organs in apiphibians is much reduced a,nd, though it is probable 

 that taste buds do exist on the skin in some larval amphibians 

 (v. Coghill, 16, 17; Driiner, 18), they are entirely confined to 

 the mouth and pharynx in adults. In considering the distribu- 

 tion of taste buds in different classes of vertebrates, Kappers 

 (38) has again drawn attention to the fact that, while the bucco- 

 pharyngeal mucosa is richly supplied with taste buds in all 

 amphibians, the number of these organs especially in the an- 

 terior part of the mouth is greater in urodeles than in anurans. 



The visceral sensory branches of nerve VII reach the mucosa 

 of the mouth in urodeles by way of the palatine and alveolar 

 rami, and in anurans by the palatine and internal mandibular 

 rami (Coghill). The greater part of the buccal mucosa, how- 

 ever, receives its visceral sensory innervation from the IX nerve 

 (Kallius), chiefly by way of the ramus lingualis. All of these 

 branches, whether conducting gustatory or general visceral 

 sensory impulses, enter the fasciculus solitarius centrally and 

 terminate in the communis area. The communis area is not 

 especially large in amphibians, and in both urodeles and anurans 

 reaches its maximum size about the level of the entering IX 

 root. Further, there is httle if any difference to be observed in 



