No. I.] THE CRANIAL NERVES OF AMPHIBIA. 151 



expected from the innervation of the heart. The ganglia in 

 the latter might be regarded as collections of the ganglion cells 

 just described. 



The remainder of the sympathetic passes within the cranium 

 through the vago-glossopharyngeal exit and forwards to the 

 Gasserian ganglion. Its destination here has already been 

 partly described. It supplies the various branches from this 

 ganglion, as already mentioned by De Watteville (66). The 

 lateral line branches appear to be, at times, unsupplied. This 

 deficiency is possibly provided for by the smaller trigeminal 

 branches, as described already (p. 1 19), from which, apparently, 

 sympathetic fibres pass over into the lateral line branches. 



Vaso-motor fibres can be seen at times coming from the 

 trigeminal branches, and they are derived from the fine, 

 probably non-medullated fibres, which are impregnated by 

 Golgi's method, and which are seen in all the trigeminal 

 branches. I have not observed any ganglion cells in connec- 

 tion with these fibres. Whether they are partly or wholly 

 from the sympathetic, I have not determined. 



5. Recapitiilatio7i of Nerve Coinp07ients. 



From the above description it is evident that we have in 

 each nerve the following components, distinguishable by the 

 nature of their fibres, their peripheral distribution and their 

 internal origin : 



Trigeminus. — {a) What may be termed general cntaneoiis 

 fibres, i.e., those supplying the skin exclusive of the specialized 

 lateral line sense organs. The majority of these fibres are small 

 but there are also among them a number of fibres of medium 

 size as well as some coarse fibres. The bulk of this component 

 is derived from the ascending trigeminal tract which is a 

 continuation of the dorsal columns of the spinal cord. The 

 ganglion (or ganglia) of this component is the ganglion of the 

 maxillo-mandibularis and ophthamicus trigemini, namely, the 

 Gasserian ganglion proper. 



{b) Motor Fibres. — These are mainly coarse, innervate the 

 jaw muscles supplied by the Trigeminus, and are derived from 

 the trigeminal motor nucleus (and descending tract.?). 



