590 



Fig. 10. 



Tectum opticum 



Valvula 

 Cerebellum 



Tr. tecto-cerebell. 

 N. trochlearis 



See. vagus comm. 



See. vagus nuc. 



Tr. lobo-cerebell. 



crossed 



See. vagus bundle 



Tr. lobo-bulb. crossed 



Terminal nuc. of 



Meynert's bundle 



Tr. lobo-bulb. direct 



Tr. teeto-bulb. 



Decussation of 



Meyneet's bundle 



Bundle x 

 Metneet's bundle 

 cerebellar portion 



but the anterior portion, which corresponds to the L. trigemini of 

 Matser is very much smaller in Acipenser than in Teleosts and is 

 composed chiefly of the root fibres of the dorsal Vllth. These fibres 

 pierce the acusticum and turn backward along the central cavity, as 

 already described by Goronowitsch (see his Figs. 15 and 50, and 

 Fig. 7 of this paper). The cells in this part of the lobe present some 

 peculiarities which need not be described here, as I believe that their 

 relations are the same as those of the cells in other parts of the 

 lobe. The name Lobus trigemini should, it seems to me, be entirely 

 dropped, as it does not properly apply to any structure in the brain 

 of fishes. 



B. Cerebellum. 



The cerebellum consists of (1) the body, which is directly con- 

 tinuous anteriorly with (2) the valvula, and laterally with (3) the 

 lateral lobes. The lateral lobes present two distinct layers: (a) an 

 inner granular layer, in which are numerous Purkinje cells whose 

 dendrites project into: (b) the outer molecular layer. In the body 



