132 J. B. JOHNSTON, 
Phot. 55 shows the decussation of fine fibres and the larger 
number of fine fibres in the right bundle. The ansulate commissure 
is scarcely visible. In Phot. 54 which is taken from the next section 
dorsad, the commissure is seen and the greater part of MEYNERT’sS 
bundle runs through the commissure without crossing. Caudal to 
that part of the commissure seen in this section (the region of the 
corpus interpedunculare) there is a long series of coarse fibres 
crossing the middle line at right angles. In this section and in 
similar sections from other series it is easy to trace individual fibres 
of MEYNERT’s bundles across the median line in this decussation, 
and undoubtedly all the coarse fibres cross here. The caudal limit 
of the decussation is marked in the photograph by the sudden 
change from coarse to fine decussating fibres. The length of the 
coarse decussation in this section is about 1,16 mm (brain of a 
fish 38 cm in length). At either side of the decussation there 
are seen in Phot. 54 dense masses which under high magnifi- 
cation are seen to consist of fine nerve twigs. Among these the 
coarse fibres after decussating turn sharply upward toward the eye 
(dorsad). The cross sections of these fibres may be traced in sev- 
eral successive sections dorsally at either side of the median raphe. 
In these and similar sections the fine nerve twigs at either side of 
the decussation have the appearance of coming in Pa at least from 
the decussating fibres. 
I have traced the entire course of these bundles in frontal 
sections and in sections cut in the transverse plane but inclined 
caudad or cephalad. It is especially in sections inclined caudad so 
as to pass through the corpus interpedunculare and the caudal part 
of the lateral lobes of the cerebellum that I have traced fine fibres 
from the region of the decussation of the fine fibres of these bundles 
to the granular layer of the cerebellum. The place of ending of 
these fibres is in reality a group of granule cells upon the lateral 
face of the lobus lineae lateralis which is continuous with the gra- 
nular layer of the lateral lobes of the cerebellum (cf. page 96). 
The coarse-fibred portion is traced as a whole without difficulty 
to the coarse decussation described in horizontal sections. In fron- 
tal sections this decussation (fig. 8) has very much the appearance 
shown in the figures of VAN GEHUCHTEN (94) and CAJAL (96). 
The fibres are coarse, somewhat sinuous, and bear a good many 
short, bract-like collateral twigs. A few longer collaterals are given 
off during the decussation. These collaterals help to form the dense 
