148 JouRNAL OF CoMPARATIVE NEUROLOGY. 
olfactory neurones of the second order. Fibres also end here 
which have ascended in the tractus strio-thalamicus, and have 
crossed over in the anterior commissure. Some of the termin- 
ations occur near the bodies of the cells, but many of the fibres 
are to be traced to a narrow zone next the lateral ventricle into 
which the dendrites of the neurones penetrate (Fig. 32, o/. f.). 
Here the fibres give off branches which run parallel with the 
limitans interna. The significance of these terminations will 
be considered under the heading of the general striatum. 
Comparing the description and figures given by JOHNSTON 
(98a) for the ganoid brain, it would seem that the epistriatum 
is the more sharply marked in Mustelus. Although found in 
an animal ranking lower in the zoological series, the fact is 
doubtless a correlative of the more powerful olfactory organs 
which characterize the selachian organization. 
6. General Striatum.—The median zone common to the 
pair of striata contains but few neurones. It is occcupied chiefly 
by interlacing fibres of small calibre. The greater number of 
these are doubtless commissural, but in the more dorsal region 
there appear to be connections with the pallium. 
The great mass of the striatum has neurones scattered 
through it without any order of arrangement (Fig. 31, si). 
These neurones are never closely crowded, there usually being 
wide intervals between the cell-bodies. Their dentrites are very 
long, however, so that an interlacing plexus is given through- 
out the whole field. Fig. 34 will illustrate these features. 
An individual neurone is shown in Fig. 35 drawn toa 
smaller scale than the other neurones of the striatum because its 
processes spread so widely. The cell-body may be rounded, 
oval, or polygonal in outline. There are numerous long and 
slender branching_dendrites. Several dendrites often arise from 
a common thick stem which might almost be considered a part 
of the cell-body. A dendrite is noteworthy for the many little 
crooks which appear in its course, and also for the peculiarly 
spine-like gemmules which beset it. The latter feature is evi- 
dently characteristic of these neurones in fishes, as VAN GE- 
