Kappers, TeJeostean and Selachian Brain. 93 



After they have attained this great size after the addition of these 

 cerebellar fibers, the fasciculi longitudinales on both sides run 

 backward decreasing very slightly in volume. To be sure, 

 farther caudad in the vagus region they do not project so strongly, 

 but this is caused by the fact that the dorsal displacement of the 

 lateral parts has already begun here. Estimating their circum- 

 ference, this appears to have remained almost the same. 



I think there is left no room for doubt that this is the same part 

 of the fasciculus dorsalis which could be follow^ed so clearly and 

 sharply in Gadus mto the motor cell column, the tr. cerebello- et 

 octavo-fnotorius cruciatiis. Edinger figures this tract, but differ- 

 ently, and I think did not accurately interpret it. In Fig. 70 of 

 the fifth edition of his " Vorlesungen" he calls this tract "tr. 

 quinto-tectalis," a name which he also uses for it in his last publi- 

 cation on the cerebellum of Scyllium canicula. He also sees this 

 tract in its subventricular course, but evidently considers it as 

 originating from the tectum, and connected with the trigeminus, 

 running through the velum. I can most positively state that the 

 tr. cerebello-motorius cruciatiis does not go through the velum and 

 that this false impression is produced only by the tecto-cerebellar 

 tract, which ends in the region of the cerebellum w^here this tract 

 begins. I am more and more doubting the existence of the mesen- 

 cephalic quintus root in fishes, like the other investigators whom 

 I mentioned in the first part of this chapter, and I think I mav 

 conclude from Edinger's way of expressing himself on this sub- 

 ject that he is by no means positively convinced of his interpreta- 

 tion. The strong development of the fasc. long, posterior of the 

 selachians Edinger himself has already brought into relation 

 with a supposed connection between this fasciculus and the cere- 

 bellum. I am, accordingly, happy to prove as a certainty what 

 he supposed. 



Now that I have described the frontal relations of the oblongata 

 (and part of the cerebellar), I may proceed to the description of the 

 nerves. 



The nervus trigeminus, which contains sensorv and motor 

 fibers, enters the oblongata at the level at which the most anterior 

 part of the lobus nervi lateralis becomes visible in the ventriculus 

 quartus (Fig. c, Plate VII). The motor and sensory fibers enter 

 at almost the same place, the motor in part somewhat anterior to 

 the sensory. From the former root one part immediately takes 



