112 Bulletin of Laboratories of Denison University. [Voi. xiii 



gustatory systems, and it was noticed by Maysek ('82, p. 325) 

 that the cephalic part of the "UebergangsgangHon" (including 

 my nucleus lateralis valvulae) varies in size with the valvula 

 cerebelli, while the caudal part (which corresponds in part with 

 our substantia reticularis grisea trigemini) varies with the size 

 of the secondary gustatory tracts. In Mormyrus, where the 

 lateral lobes of the valvula attain so enormous size as to expand 

 upwards and laterally in mushroom shapeand overlap the whole 

 brain, Sanders ('83) describes also a considerably enlarged and 

 modified tuberculum impar and vagal lobes. Since the other 

 parts of this brain are of the typical teleostean type, save for 

 the reduction of the visual apparatus and inferior lobes, it ap- 

 pears probable that the lateral lobes of the valvula are related 

 with the gustatory reflexes. 



The chief connections of the cerebellum are with centers 

 commonly regarded as of the somatic sensory type — tactile, 

 acustico-lateral, visual. This strengthens the current view that 

 this organ is concerned with the regulation of somatic move- 

 ments, or reactions of the body to external stimuli as distin- 

 guished from visceral reactions to internal stimuli. A gusta- 

 tory cerebellar connection would seem, therefore, very anom- 

 alous. And so it would be in an ordinary vertebrate, if our 

 present functional analysis is proceeding along true lines. But 

 we have seen above that the fishes here under consideration, 

 unlike most other vertebrates, make somatic movements in re- 

 sponse to cutaneous gustatory stimulation in their ordinary 

 feeding reactions. This feature gives an abundant explanation 

 for the cerebellar connections of the secondary gustatory nu- 

 cleus, by way of the nucleus lateralis valvulae, as well as a pos- 

 sible clue to the morphology and phylogeny of the valvula. 



The problem of the relation of taste and smell is of major 

 importance from the points of view of comparative physiology, 

 of phylogeny and of morphology. Why the single chemical 

 sense of some invertebrates should have given rise in the verte- 

 brates to two systems so distinct morphologically as the olfac- 

 tory and gustatory apparatus has not been explained. A sug- 

 gestion of a possible genetic connection is manifest in the ac- 



