98 J. B. JOHNSTON, 
T-shape. One branch of each fibre passes together with its fellows 
in a compact bundle caudally along the lateral surface of the body 
of the cerebellum and breaks up in somewhat profuse end-branches 
in the granular layer and especially in relation with the large cells. 
Only a few of the tips of these end- 
à Ära branches enter the molecular layer 
an in the keel at the caudal end of 
the body. The other branches of 
the fibres of this tract diverge in 
/ the valvula without regular ar- 
À rangement. Immediately ventral to 
\ this bundle another and larger 
1 / a) bundle from the tectum enters the 
cerebellum, the tractus tecto-cere- 
bellaris II (Pl. 13 and Fig. E). 
/ This second bundle comes from 
the middle layer of the tectum, and 
consists of fine and coarse fibres 
which, when they enter the cerebellum, diverge in all directions to 
end in the valvula and in the granular layer of the body and of 
the lateral lobes. 
In the lateral wall of the mid brain there is a very large tract 
of fibres which come from the cells of the lobi inferiores by way of 
the decussatio postoptica and are destined to end in the cerebellum 
and medulla. This is the tractus lobo-cerebellaris et bulbaris cru- 
ciatus (Pl. 13, see page 154). When this tract comes opposite the 
bridge between the cerebellum and the lateral walls of the mid- 
brain, it sends a small part of its fibres into the cerebellum. Farther 
caudally a second, larger, bundle enters the cerebellum, and later 
a third bundle enters the cerebellum and decussates with its fellow 
of the opposite side, forming the largest of the commissures through 
the body of the cerebellum. The remainder of the tract passes on 
into the medulla. Along with these bundles there enter the cere- 
bellum two other bundles, one of fine and one of coarse fibres, from 
the lobi inferiores, the tractus lobo-cerebellaris et bulbaris rectus 
(Pl. 15, see page 134). The fibres of all these bundles become so 
mingled after they enter the cerebellum that it is impossible to trace 
them separately, and I am inclined to believe that their distribution 
is the same, viz., to the granular layer of all three divisions of the 
cerebellum. It is noteworthy that the cells of the II type are most 
numerous among the fibres of these tracts. 
