94 The Neuroglia of the Spinal Cord of the Elephant 
as above, point toward the spaces between the neighboring nerve fibers. 
The balance of the inter-axone space is clear and the neuroglia fibers 
coursing through it are sharply differentiated. The fibers occupy the 
clear area chiefly, but often they penetrate the cytoplasm and even cross 
the nucleus (c, Figs. 2 and 4). When the mass of cytoplasm (endo- 
plasm) is quite scant it sometimes appears on one side of the nucleus 
only but is usually pointed, suggesting one of the projections of a pre- 
viously more abundant cytoplasm. The nucleus of this type is also of 
the large vesicular variety. Representatives of this type of cell may 
Fie. 3. From transverse section showing four types of neuroglia cells (0, ¢, d, 
and i) and the arrangemént of the neuroglia fibers with reference to the cell and the 
inter-axone space. One neuroglia fiber () appears continuous through the domain of 
several neuroglia cells. The colors represented by the different shades of black are 
the same as those in Figures 1 and 2. 1l=leucocyte. x 940. 
be seen in most any field of the microscope. In his comparative “ Stu- 
dies on the Neuroglia,” Huber (loc. cit.) describes this type, and I think 
also the second type I have mentioned, for the dog, cat, rabbit, dove, 
tortoise and frog, and such have been noted in the human. 
4, Cells with but a very small amount of cytoplasm about the nucleus 
forming a sort of granular halo about it (d, Figs. 3 and 4). Projections 
are seldom apparent. Neuroglia fibers traverse its inter-axone space 
indiscriminately, frequently crossing the nucleus above or below it. The 
fibers are more abundant in these areas than in any of the above types. 
They enter and leave by way of the spaces between the adjacent nerve 
fibers and often one may be traced through the domain of a neighbor- 
