90 BULLETIN OF THE LABORATORIES 



themselves into the reticulum in which they lie. In only a few cases 

 have actual anastomes been observed. The nuclei are large and elon- 

 gate and there is a marked tendency for small corpuscles to associate 

 themselves about the base between the spreading branches of these 

 cells. 



In some cases, especially toward the ental fibre layer the pyra- 

 mids are reversed and the apex process passes centrad. Near the con- 

 tact with the white matter the cells are rather multipolar than pyramid- 

 al and their chief process appears to pass into these fibre tracts. The 

 white fibre layers at the surface in this region seem to be derived from 

 the radix lateralis of the olfactory. Longitudinal sections seemed to 

 indicate that the lateral radix divides or other fibres become associated 

 with it, at least a band of obliquely-cut fibres may be seen ectad to 

 those are passing directly caudad. The latter portion is thought to 

 pass obliquely over the median surface to the hippocampus while the 

 ectal portion seems to spread out in diminishing quantity upon this 

 region The vast quantity of fibres overspreading this region (i. e. 

 lateral and ventral part of pyriform lobe) seems to preclude the possi- 

 bility of all having been derived from the radix lateralis. The ventral 

 regions of the pyriform exhibit pyramids mingled with large multipo- 

 lar or fusiform cells with large clear circular nuclei. In some cases it 

 seemed probable that the axial processes of the pyramids first described 

 suddenly turn as they reach the neuroglia layer. In other cases and 

 in the case of the superficial multipolar cells the is no doubt that the 

 processes subdivide very minutely. This region of the neuroglia is so 

 filled with non-medulated fibres as to stain more deeply than other re- 

 gions. We seem here to have a neuropilem in the sense suggested 

 by Koelliker. 



In the infra-rhinal type of cortex strands of fibres may often be 

 seen passing from the ectal nervous reticulum between the cells to- 

 ward the central white matter. This is especially apparent at the 

 caudal extremity of the pyriform lobe. 



Cortex of Occipital region. In the lateral aspect of the occipital 

 region dorsad of the rhinalis fissure we encounter a commingling of 

 two distinct kinds of cells. The pyramidal cells are present over most 

 of the cortex, being most numerous peripherally. They can be recog- 

 nized by the deeply stained elongate nucleus and form of the cell. 

 The second class consists of cells of a fusiform or pyriform (i. e. flask) 

 shape. With the selective stains used, haematoxylin and Hg Ch, the 



