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. 



FIG. 90. The generative" organs of the male Blow-fly, de, ejaculatory duct ; es, 



ejaculatory sac ; /, penis ; pg, paragonium ; 

 efferens. 



testis ; vd, vas deferens ; ve, vas 



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. 



