HISTOLOGY OF THE CENTRAL NERVOUS SYSTEM OF THE WEDDELL SEAL 851 
The postero-lateral and intermedio-lateral masses of grey matter are united by 
strands of neuroglial tissue, which break up the lateral regions of the cord into a well- 
marked reticular formation. The grey matter in general is characterised by its deeply 
staining neuroglia fibres, which are of a somewhat coarse nature, and are apparently 
Jess in number per unit area as compared with the supporting tissue of higher types 
of cord. 
| Poe 
a. #. Qn 
Fic. 1.—A transverse section of the spinal cord (upper cervical region). 
a.f. Anterior median fissure. p.h. Posterior horn of grey matter (beginning 
p.f. Posterior median fissure. of the substantia gelatinosa of Rolando), 
p.r. Posterior root-bundles, i.U.h. Intermedio-lateral horn. 
a.r, Anterior root-bundles. f.r. Formatio reticularis. 
fg. Funiculus gracilis (posteriormediancolumn), a.h. Anterior horn. 
showing an indication of the beginning p.m, Pia mater. 
of the nucleus gracilis. 
In the central region of the section the posterior grey commissure is of wide extent, 
and a small amount of neuroglia is to be seen anterior to the central canal of the cord : 
the latter is flattened antero-posteriorly, and is lined by a well-marked layer of 
columnar ciliated epithelium. 
The postero-median fissure is of about the same length as the anterior median 
fissure, perhaps slightly longer; but the cord has apparently been subjected to a certain 
amount of mechanical pressure, causing flattening, and giving the whole section the 
appearance of abnormal transverse as compared with antero-posterior diameter. - The 
