242 FISH. [Vou X. 



nerve where it subdivides, one branch going to Jacobson's 

 organ, the other to parts cephalad of the eye. The maxillary 

 branch joins the ganglion a little dorsal to the mandibular, both 

 extend laterally, but were not traced for any length. 



VI. The abducens arises from the ventral aspect about mid- 

 way between the origins of the eighth and ninth. It is a very 

 slender nerve and passes off toward the Gasserian ganglion, 

 but a distinct union with it was not demonstrated. Kingsley 

 (19) did not find it in a larval Afnphiimia. Although very 

 minute and easy to escape detection it is generally believed 

 to exist m. Amphibia. Mrs. Gage (13) found it in the adult 

 Diemyctylus, but only a trace of it in the larva. 



VII, VIII. The facial and auditory nerves are apparently 

 fused into one trunk. The combined root is just caudal to and 

 in line with the fifth. It would appear that the portion corre- 

 sponding to the eighth is slightly cephalo-ventral to the caudal 

 branch of the seventh. From the common trunk there passes 

 a good sized branch toward the dorsal surface of the Gasserian 

 ganglion, but I failed to establish an actual union; it probably 

 corresponds to the palatine branch. The other, the hyomandib- 

 ular, arches latero-caudad. In the angle of divergence between 

 these two branches and more to the ventral side of the trunk 

 lies the auditory nerve joining with the ear capsule by two or 

 possibly three divisions. The eighth nerve is ordinarily repre- 

 sented as extending caudad of the seventh, and it seems quite 

 likely that its more forward position in this form may be due 

 to a cephalo-caudal compression of the head parts. There are 

 other features connected with the brain which seem to warrant 

 this view. 



IX, X, XI. The glossopharyngeus, vagus, and spinal acces- 

 sory arise by separate roots, that of the tenth being the largest 

 and forming apparently the chief part of the trunk of which 

 the other two are simply reinforcements. All three arise about 

 in a line and nearer the dorsal than ventral margin. A short 

 distance out there is a ganglionic enlargement. From the gan- 

 glion three branches are given off ; one passing cephalad con- 

 necting with the seventh, the other laterad, and the third and 

 largest caudad. 



