Herrick, Cranial Nerves of the Cod Fish, 31 1 



r. cutaneous dorsalis. Now, if the distribution area of this 

 nerve were to be shifted forward so that these vagal general 

 cutaneous fibers should accompany the r. lateralis accessorius 

 cephalad from the anastomosis, the condition given in the tad- 

 pole would be realized by the exaggeration of this vagal general 

 cutaneous component and the reduction of the communis com- 

 ponent which primitively composed the r. accessorius. The 

 significance of the intra-cranial anastomosis from the vagus to 

 the facialis in Batrachus (marked com. VII — X on Miss Clapp's 

 diagram) is obscure. It may represent an intra-cranial (com- 

 munis) vagal root of the r, lateralis accessorius or Jacobson's 

 anastomosis, or it may even be the sympathetic trunk between 

 the vagus and facialis. In either of the latter cases there would, 

 however, be two points requiring explanation, viz., its intra- 

 cranial instead of extra-cranial course and its connection with 

 the vagus instead of the glossopharyngeus root. 



IV. Summary. 



This study extends our knowledge of the exact composi- 

 tion of the cranial nerves to another species and shows that Ga- 

 dus and Menidia agree substantially in the composition of the 

 cranial ganglia and rami. We are, accordingly, entitled to infer 

 with still more confidence that this arrangement in its broad 

 outlines is characteristic of the Ichthyopsida as a whole. The 

 chief points of difference between the cod and Menidia are pre- 

 sented at the beginning of the third part of this paper. 



I have in the main confirmed Cole's results in his recent 

 researches upon the nerves of the genus Gadus, except in the 

 case of the facial ganglion and r. lateralis accessorius. The 

 latter nerve is composed chiefly of visceral sensory or communis 

 fibers and it is distributed to terminal buds in the vicinity of 

 the fins. The facial ganglion is entirely distinct from the Gas- 

 serian and also from the sympathetic and the cod does not ex- 

 hibit any evidence that the communis system of nerves in gen- 

 eral or the facial (geniculate) ganglion in particular is in a state 

 of transition from a cerebro-spinal to a sympathetic type of 

 nervous structure. 



