660 



GERARDA STIASNY- WIJNHOFF 



each case we see the tendency of the gonads, whether testes or 

 ovaries, to arrange themselves metamerically and become 

 reduced in number. 



In the Pelagica the differences of sexes are greater. The 



Sections through the gonadial region: a, of Drepanophorus 

 willeyanus (Punnett) (14, PI. lix, fig. 20); h, of Siboga- 

 nemertes weberi. 



Text-fig. 24. 



Section through Drepanophorus albolineatus with an 

 ovary after Burger (6, PI. xxvii, fig. .52). 



ovaries are metamerically developed, never more than one 

 between two intestinal pouches, but the gonopores lie on the 

 ventral side. This may be the case in Drepanophorus too 

 (Text-fig. 24). In broader and flattened forms the body becomes 

 thin with flat edges, outgrowths of the body-wall and paren- 

 chyma, that in certain species contain no organs at all, in others 

 rhynchocoelomic diverticula only. In some of these species it 

 is quite obvious that the outgrowth took place above the 



