V. Kltffeh, Cranial Xcrvcs of \ crtcbratcs . 317 



is somewhat smaller than the second, and has an approxi- 

 mately triangular shape, the base directed dorsad. It lies 

 over the eye. From the fore corner there go out two stout 

 nerve trunks, which proceed in an arch cephalad and ven- 

 trad. In the ganglion two portions may be distinguished. 

 Tlie dorsal, broader part is traversed by fibrilLne which pro- 

 ceed, in direction, from the roots to the branches; in the 

 ventral, tapering part no fibrillre can be perceived among the 

 nerve cells. 



The second principal ganglion, more voluminous than the 

 first, has also a stouter root (perhaps already two). It lies 

 over the stomodseum and likewise displays two divisions, 

 which have the same relations as those of the first principal 

 ganglion; fibrillfe traverse the fore dorsal part, the hinder 

 part appear free of fibrillas. From the fore part there go 

 close together the two branchial nerves, the N. maxillaris 

 and N. mandibularis. Both consist of a compact cord of 

 fibres, which contains nuclei within, and at the surface 

 shows an envelope of cells. 



The epibranchial ganglia of this region show a continuous 

 chain which impinges cephalad upon the lens, so thai it 

 appears as the foremost part of the chain. One can distin- 

 guish between the lens (it not being reckoned in) and the 

 N. mandibularis, three parts of the chain, marked oft' by 

 constrictions, which may be designated the first, second and 

 third epibranchial ganglia. The first is inserted slightly 

 under the lens, the second projects somewhat dorsally and is 

 directly connected with the first principal ganglion. The 

 third epibranchial ganglion lies at the lateral side of the 

 origin of the NN. maxillaris and mandibularis, and stands in 

 broad connection with the cell mass of the second principal 

 ganglion. 



2. Region of the Acustico-Facialis. — The fi^cial ganglion 

 and the auditory vesicle of the principal ganglia belong to 

 the series. The principal ganglion of the facial projects far 

 forward over the auditory vesicle, and its fore end lies under 



