Kingsbury, Oblongata in Fishes. 13 



geons) led me to examine the oblongata and especially the 

 " lobus trigemini." As described by Goronowitsch there oc- 

 curs dorsad of the cerebellar crest in the region of the Vlllth 

 nerve and extending cephalad, an area of cells and fibers from 

 which springs a nerve root (his Trigemimis II dorsalis). Imme- 

 diately beneath the cerebellar crest issues another root of coarse 

 fibers, clearly Vllb of Amia. The fibers of the dorsal root are 

 indeed finer than those of the more ventral, but the difference 

 is not nearly as marked as one might suppose, and as compared 

 with the fibers of Vllaa, they are coarse. Trig. I ventralis of 

 Goronowitsch was found upon examination to spring, in several 

 rootlets from a motor nidus and not from the posterior longitu- 

 dinal fasciculus, representing the motor portion of the Vth in 

 Amia. The tract named by Goronowitsch "system Y '' is 

 clearly both from the description and the examination of the 

 brain, what was found in Amia to be part of the spinal Vth 

 tract, and from the examination of Acipenser the same seems to 

 be the real destination of this tract there. System 7 would not 

 in any case be more than a partial homologue of the second- 

 ary vago-trigeminal tract of the teleostean brain. The fact re- 

 mains, that Acipenser possesses a root of comparatively coarse 

 fibers, which is not present in Amia and Lepidosteus, springing 

 from a portion of the brain which is also apparently lacking in 

 these two forms. This the " lobus trigemini " will prove, I be- 

 lieve, to be the homologue of the structure of the same name 

 in Elasmobranchs. 



Teleostei. As compact a discussion as possible of these 

 regions and their modifications in teleosts follows. 



Nematognathi. In view of the belief of some that the 

 Nematognathi among teleosts are the most closely related to 

 Ganoids, we might expect Amiunts to show in the structure and 

 morphology of its brain, some indications of ganoid affinities, 

 but as has been already stated by C. J. Herrick '91, it presents 

 as purely teleostean characters of the brain as other bony fishes, 

 although simpler in some respects than many, — perhaps most, 

 — other Teleosts. The morphology of the oblongata and the 

 more striking and important structural features have been pre- 



