Herkick, Gustatory Paths in Fishes. 449 



en." Mayser ('82, p. 334) identifies the "Uebergangsgang- 

 lion" with the corpus quadrigeminum posterius of Fritsch 

 ('78). From the latter's figures, I infer that he included under 

 this term the structures adjacent to the secondary gustatory nu- 

 cleus as far as cephalad as my nucleus lateralis valvulae. The 

 latter nucleus is apparently included in the "cells of the super- 

 ior and internal regions of the torus semicircularis" of Catois 

 ('01, p. 133). Catois' "cells of the external region of the tor- 

 us" constitute the nucleus lateralis mesencephali of Edinger. 

 EuiNGER states that the "Uebergangsganglion" of Stieda 

 (sekundare Vaguskern) is homologous with his ganglion isthmi 

 ('96, p. 94 and '03, p. 75). He also identifies ('04, p. 194) the 

 ganglion isthmi with the nucleus tegmenti dorsalis of von Gud- 

 DEN and thinks it probably is the same as Bechterew's corpus 

 parabigeminum. Edinger adds ('04, p. 267) that the ganglion 

 isthmi of lower vertebrates receives the median root of the op- 

 tic nerve and gives rise to centrifugal fibers for the retina. His 

 account make it probable that his ganglion isthmi sould be iden- 

 tified with my nucleus lateralis valvulae rather than with the 

 "Uebergangsganglion" as a whole. Though I have not traced the 

 fibers of the mesial optic root so far caudad as this, yet the 

 connection with the post-optic commissure, referred to by 

 Edinger, is very plain, and the tract running from the cephalic 

 end of the n. lateralis valvulae to the oculomotor nuclei lends 

 probability to the belief that the n. lateralis valvulae is in part 

 a path for oculomotor reflexes and probably also somatic mo- 

 tor reflexes via the fasciculus longtitudinalis, of optic, gustatory 

 and perhaps olfactory origin. My n. lateralis valvulae is appar- 

 ently included in the "ganglio subcerebelloso" described ('94, 

 p. 96) and figured ('94 a, Fig. 4, p. 203) by Cajal. His fig- 

 ure shows the cells provided with a single thick unbranched 

 dendrite which comes into relation with collaterals from the 

 ventral longitudinal tracts of the mid-brain. 



The only conclusion at present possible is that the "Ue- 

 bergangsganglion" is a very complex structure, devoted large- 

 ly to gustatory reflexes and coordinations of several sorts, and 



