MANUAL OF ZOOLOGY 



SECT. 



aperture, and gives exit to a pair of needle-like chitinoid 

 bodies, the penial seta (pn. s.). In the female the reproduc- 

 tive aperture or gonopore is separated from the anus, and is 



situated on the ventral surface, about one-third of the length 

 of the body from the anterior end (Fig. 76, gnp.). 



The outer surface of the body is furnished by a delicate, 

 transparent, elastic membrane, of a chitinoid nature, the 



