No. I.] THE CRANIAL NERVES OF AMPHIBIA. 153 



{c) Fasciculus communis fibres similar to Facialis (b), its 

 distribution being to the alimentary canal and its outgrowths 

 caudad of the area of distribution of Facialis {b). There seem 

 to be at least three ganglia belonging to this component, one 

 of these being a portion of the ganglionic mass mentioned (A) 

 and the other two the two ganglia lying farther out on the 

 trunk of the IX + X (ganglia B and C). 



(d) Motor fibres probably similar to Trigeminus {b). 



Besides the above there are other portions of the IX + X 

 whose nature and position is not clear. One of these is the 

 "fasciculus solitaritcs " mentioned by Osborn, but erroneously 

 so called (vide infra, p. 186), and which is also present in the 

 tadpole. It is almost certainly motor. 



Rearranging the above, we have at least four components : 

 I. Gc7ieral cutaneotis, including V {a) and IX + X {a). 



II. Special cutaneous, or lateral line, including VII {a) and 

 IX + X iP). 



III. Fasciculus commjinis, including VII {b) and IX + X (c). 



IV. Motor, to branchial muscles (including jaw), including 

 V {b),Yll (r), and IX + X (d). 



It is not to be supposed that this forms an exhaustive 

 analysis of these nerves. Reasons may easily be adduced 

 from this research, as well as from other sources, to show that 

 this analysis is not complete. It is carried as far as can be 

 conveniently done with the means employed, and will form a 

 basis for additional results in the future. 



III. Comparative Morphology of the Components. 



I . General Cutaneotts. 

 General Cutaneous Component. — V {a) and IX + X {a). The 

 part of the V belonging to this component is very constant 

 apparently in the vertebrate series. We find that the Trige- 

 minus has an ascending tract from the spinal cord in Petro- 

 myzon (Ahlborn), in Acipcnser (Goronowitsch), in Selachians 

 (Rohon), and in Tcleosts (Mayser, Wright). Furthermore, this 

 tract seems subject to less variation in size than other tracts 

 and the character of its fibres is about the same. As seen 



