MR. A. SANDERS ON THE ANATOMY OF THE 
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a layer of medullary fibres. A section through the olfactory lobe of a Teleostean 
observed from before backwards, is comparable to the above-described section made 
from without inwards; first come the layer of fibres from the olfactory nerve com- 
parable to the external layer, then the layer of nodulated masses of neuroglia and 
coarse granules comparable to the stratum glomerulosum, then the finely granular 
neuroglia with sparsely scattered cells, comparable to the external part of the stratum 
glomerulosum, then the central group of small cells comparable to the internal part of 
the same stratum, and finally the thin layer of fibres which form the commissure to 
the cerebral lobes, which are comparable to the internal layer of medullary fibres above 
mentioned. 
Cerebrum or Cerebral Lobes. 
The lobi cerebri are invested under the pia mater by a single layer of epithelial cells 
of the columnar variety ; each of these cells gives off from its inner extremity a long 
fine process, which passing into the substance of these lobes is lost in the neuroglia. 
A finely granular neuroglia occupies the greater part of the cerebral lobes, in which 
cells of various sizes are scattered in varying proportions ; these cells range in size 
from 0 014 millim. long by O'OIO millim. broad, to 0'007 millim. by O'OOo millim. ; 
the smallest cells (fig. 16, a.) are generally pyriform in shape, each with a com- 
paratively lai'ge nucleus, to one side of which a conical, more or less elongated mass of 
protoplasm is attached, from the pointed end of which a nerve-fibre emerges. 
Occasionally, cells (fig. 16, b.) occur which have two diverging processes, the nucleus 
being attached to the middle and projecting two-thirds of its circumference from the 
protoplasm. These smaller cells seldom show a distinct nucleolus, but more often only 
scattered granules, as if the nucleolus had been broken up. This kind of cell (fig. 17) 
occurs more frequently near the outer edge of the cerebral lobes, and in some places forms 
a layer of cells beneath the epithelium three or four deep, with scarcely any neuroglia 
between them. They do not form a connected layer throughout the border of the 
cerebral lobes, but only occur in places ; at other parts the neuroglia extends quite to 
the inner surface of the epithelial cells. 
The neuroglia increases in quantity towards the centre of the cerebral lobes, while 
the cells decrease in number, but at the same time become larger in size ; these are 
either bipolar or tripolar cells (fig. 16, c.), in which distinct nuclei are visible, which are 
always placed either on one side of the tripolar or at one end of the bipolar cells. 
It thus happens tha.t some part of the nucleus always projects, bare of protoplasm, into 
the space of neuroglia which surrounds the cells on all sides ; generally they are only 
held in position by their processes, for which the neuroglia often forms hollow sheaths, 
in which the processes occasionally extend some distance. It seldom happens that a 
distinct nucleolus is observable in the nucleus, but usually only granules, which sometimes 
are found grouped together in the centre, as if the nucleolus had just broken up. 
That the spaces mentioned above are lymph spaces has been conclusively shown by 
Obersteiner (78), who not only observed lymph corpuscles in the corresponding 
