MANUAL OF ZOOLOGY 



SECT. 



bodies, the penial seta (pn.s}. In the female the repro- 

 ductive aperture or gonopore is separated from the anus, and 



1 31 



is situated on the ventral surface about one-third of the 

 length of the body from the anterior end (Fig. 82, gnp). 



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

 transparent, elastic membrane, of a chitinoid nature, the 



