INTERNAL GENERATIVE ORGANS OF THE MALE. 661 
processes of which reach the cell wall or similar processes 
from other nuclei; the interspaces are clear vacuoles filled with 
fluid or, more rarely, with oil globules (see pp. 275, 276). They 
are exhausted, or semi-exhausted fat-cells, and form the peri- 
toneal coat of the organ. 
Fic. 90.—The generative’ organs of the male Blow-fly. de, ejaculatory duct ; es, 
ejaculatory sac ; ~, penis; Ag, paragonium ; ¢, testis ; vd, vas deferens ; ve, vas 
efferens. 
In the advanced pupa and the mature insect before the act 
of copulation, the interior of the testis is divided into loculi by 
processes or septa from the epithelial coat. These septa are 
exceedingly delicate and bound irregular spaces; those towards 
the fundus of the organ are packed with spermatogenic cells, 
and those nearer the duct contain fully developed spermatozoa. 
