82 
BULLETIN OF THE LABORATORIES 
is a layer of ganglion cells. These cells are pyramidal and give off 
three or more acute projections peripherally, but extend into a thick 
axillary process below. The number of ganglion cells is relatively very 
small. The bases of these ganglion cells are immersed in a dense zone 
of neuroglia nuclei, which are oval and furnished with very prominent 
nucleoli, one always being central, they are not more than one-fifth 
the length of the ganglion cells, and their function may be to nourish 
the ganglion cells and insulating layer of the centripital nervous pro- 
cesses. The following layer is composed of nerve fibres, which are 
collected in bundles closely invested by nuclei similar to those above 
described and divided into upper and lower tracts by the olfactory 
ventricle. The dorsal part of the crus olfactorius has a cortical layer, 
differing materially from that of adjacent parts of the cerebrum. 
The course of the fibres is difficult to trace in detail. There are 
two distinct tracts, the upper passing directly to a point below ventral 
point of the lateral ventricle, partly mingling with the cortical fibres 
of that region and passing through the base of the corpus striatum, but 
giving off a branch which unites with the lower superficial tract which 
passes obliquely backward upon the surface to what has been called 
the pyriform lobe. 
Fig. 9, Plate I. Transverse section of olfactory lobe. (a,) gran- 
ular layer, (b,) gelatinous layer, (c,) position of ventricle, (d,) gang- 
lion layer, (g.) glomerular layer, (f,) fibre tracts. 
Fig. I, Plate II. Longitudinal section of anterior part of hemi- 
sphere and olfactory lobe. Fig. la, fibre bundle, enlarged. Fig. 3, 
Plate II, section through ganglion and adjacent layers, much enlarged. 
Fig. 2, Plate II, portion of cortex at base of crus olfactorius. 
[Note.] — Although most of the time devoted to this paper has 
been employed in the study of the histology, especially of the cortex, 
his section must be omitted till the next issue, because of vexatious 
delays. 
