371 



the fibers of the whole radix come near the large-celled nucleus, so 

 far as Weigert preparations show. 



In cyclostomes the relations of this tract require further study. 

 It has not been described, I believe. In Lampetra no fibers going 

 forward from the trigeminus are to be seen in hsematoxylin sections 

 cut in such planes that they seem quite conclusive. In Golgi sections 

 a relatively small number of fibers to the cerebellum have been de- 



Fig. 6. Fig. 8. 



Fig. 5. Transverse section through the root of the trigeminus in Necturus. 



Fig. 6. Necturus. Tnansverse section behind the cerebellum. 



Fig. 7, Necturus. Transverse section through the cerebellum and the caudal 

 part of the tectum opticum. 



Fig. 8. Necturus. Transverse section through the cephalic part of the cerebellum 

 where it overlies the tectum. Figs. 7 and 8 are each combined from several sections 

 and together show the whole course of the radix mesencephalica through the cerebellum 

 and into the tectum. 



scribed by the writer. In Petromyzon dorsatus a bundle of very 

 coarse fibers from the sensory root of the trigeminus is traced forward 

 through the raeso-dorsal part of the acusticum and through the cere- 

 bellum to its junction with the tectum. Here the fibers bend mesially 



24" 



