George L. Streeter 



17 



central canal held in suspension by a few coarser strands of glia fibres 

 which lie among the cells and bridge over the space separating the grey 

 matter. I'liis meshwork formation of these modified glia cells extends 

 somewhat into the territory of the white substance along the borders of 

 the dorsal, lateral and ventral funiculi. Under low power this ragged 

 edge of white substance gives the deceptive appearance of an artifact. 



From the 38th segment caudalward there is a gradual retrogression of 

 neuroglia to the form as previously described. 



Invasioaof v/hite substance. 



Lal.Jroup gang ce. 



Nucl. margindli 

 major- 



Ligamenlum denlic 

 Psnph glia unmodified 



Periph glia modified 



Ligamenlum long'ventr 



L gameiilum long lal, 

 (Ligamentum dcntic) 



Ventral root fibres. 



Anterior commissure 

 Central C=ip.il 



Fig. 5. Cross-section of the lumbo-sacral enlargement of the ostrich spinal 

 cord, ai the 36th segment, enlarged 12 X- A portion of the sinus rhomboideus 

 tissue is shown above with an enlargement of 270 x- 



Central Canal. 



The cylindrical epitlielial cells lining the central canal form a layer 

 .007 to .015 mm. thick which is supported by a thick mass of glial tissue, 

 2 • 



