$8 Btilletin of Laboratories of Denison University. [Voi. xii 



enlargement of the cephalic end of the gustatory center (vagal 

 lobe) which appears on the dorsal surface of the oblongata as 

 the facial lobe. This structure is paired in siluroids and was 

 formerly called the lobus trigemini, an inadmissible term, since 

 it has nothing whatever to do with the trigeminus nerve. In 

 cyprinoids it is unpaired and is referred to in the older literature 

 as the tuberculum irnpar. 



The cyprinoid fishes also have long been known to have 

 terminal buds {Bec/ierorgatie) widely distributed over the outer 

 body surface; but neither the innervation of these organs nor 

 the exact composition of the cranial nerves has ever been worked 

 out in any cyprinoid fish. A cursory examination of a series of 

 sections prepared by the Weigert method through the entire 

 head and body of a small gold fish [Carassiiis aiiratus) has con- 

 vinced me that the same conditions in general prevail in the 

 cyprinoids as in the siluroids. That is, the enormous size of 

 the vagal lobes of cyprinoids is explained by the fact that these 

 are the terminal centers for the vast numbers of nerve fibers en- 

 tering the brain by way of the IX and X nerves from the pala- 

 tal organ, this remarkable structure being crowded over its en- 

 tire extent with taste buds and probably serving to filter food 

 particles out of the mud taken into the mouth. 



On the other hand, the tuberculum impar, or facial lobe, 

 receives the entire communis root of the facial nerve. This 

 root receives fibers from practically all parts of the outer surface 

 of the body, and we may infer by analogy with other fishes that 

 these fibers connect with the terminal buds in these cutaneous 

 areas, though we have as yet no actual demonstration of this 

 fact. The terminal buds of the skin of the head are supplied 

 mainly, as in Anietmus, by way of the infra-orbital trunk. The 

 terminal buds in the skin of the body of the gold fish are not, 

 however, supplied by a ramus lateralis accessorius, or recurrent 

 facial nerve, as in Ameiutus and the gadoid fishes, for this 

 nerve, as has long been known, is absent in the cyprinoids. 



There is, however, in these fishes an intra-cranial anasto- 

 mosis between the V+VII ganglionic complex and the IX-}-X 

 complex, the composition of which has thus far remained un- 



