751 



to be stunted and without their long fine prolongation. Some of the 

 examples are very large, others quite small, but together they fill up 

 the whole space along the margin of the ventricle in this region. 

 There are no transition forms between these neuroglia cells and the 

 more usual varieties in tbeir neighborhood, and they are stained in 

 no other location than along the immediate margin of the ventricle. 



A little outward from the ventricular edge, we begin to meet 

 with cells approximating the short rayed Golgi glia cells in shape, 

 but their bodies are of rather larger size, the tentacles coarse, not 

 reaching to the ventricular border (8, fig. 1), and it is only when 

 we approach a region about 3 mm from the pial .border of the basis 

 cerebri, and some considerable distance from the ventricle, that the 

 distinctly glia cells of the long rayed type first make their appearance, 

 and are then very numerous and closely placed together, their rays 

 interlacing in all directions. In specimens in which the neuroglia is 

 fully stained, the meshwork formed by the prolongations of these 

 cells is so dense, even without the admixture of nerve fibrillae, that 

 under low powers this whole portion of the section is stained almost 

 a solid black. 



Returning now to the floor of the brain lateral to the ventricular 

 cavity, we again see the shapes of the neuroglia cells change com- 

 pletely. The embryonal types have everywhere departed, and in their 

 places, ranged along the inferior edge of the brain floor, and also 

 from thirty to sixty mikrons above it, are stout bodied cells of irregular 

 shape (10, 11, fig. 1), with processes, extending in all directions, 

 interlacing with each other, and forming a grill-work, but never anasto- 

 mosing. Two chief types of cells may here be differentiated. The 

 first (fig. 1, nos. 10), are cells with irregular bodies, and with a vast 

 number of rays extending from all portions of the cellular protoplasm, 

 but with several thicker processes extending upwards into the cerebral 

 substance, and a number, often very considerable, of shorter ones, 

 passing to the pial limit, where they end with ball-like knobs. The 

 lateral rays from these cells are very numerous and strong, and help 

 largely to form the interlacing network along the margin of the brain 

 floor. 



The second form (fig. 1, no. 11, and fig. 4), is an extremely 

 angular cell having quantities of hair-like projections from the cellular 

 body and basal portions of the thicker processes. The processes 

 themselves are not so numerous as those of the former type, and are 

 only notable by arising from the body by thick junctures, and then 

 gradually diminishing in calibre. Among the extensions one may 



