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JOSE F. NONIDEZ. 



larged portion (Fig. 2, c) placed against the proximal surface 

 of the sac. The whole organ may be compared with two kidney- 

 shaped hollow bodies fused along a sagittal plane, their cavities 

 being confluent. The single cavity thus arising is lined with a 

 thin cuticle produced by the columnar epithelium (w) which 



FIG. i. Male generative organs of Drosophila melanogaster, ventral view. 

 d, vas def erens ; e, ejaculatory duct; p, penis; pr, paragonia ; s, ejaculatory 

 sac ; t, testes ; v, vasa eff erentia. 



forms the walls of the organ, and contains a highly refractive, 

 thick fluid (/) secreted by the epithelium. This fluid is scanty in 

 young flies, a small amount being present in those just hatched. 

 It is entirely separated from the outside since the cavity in which 

 it is contained has no outlet. In the proximal surface of the sac 

 the cuticle secreted by the epithelium is thickened to form a plate 

 bearing a rod-shaped sclerite (s) which projects freely into the 

 body cavity. The sclerite is connected with the outer walls of 



