T. B. ROSSETER ON DREPAXIDOT^NIA VENUSTA. 23 



Fig. 9. Transverse section of papilla previous to coitus, showing 

 cirrus more fully everted than in the previous figure ; 

 also vaginal orifice and longitudinal muscles of vaginal 

 canal, x 93. 



Fig. 10. Male and female genital organs in situ, aa' a\ testes; 

 h y y\ vasa efferentia of same ; c, looped vas deferens, 

 c", looped vas deferens, interior of pouch, containing 

 spermatozoa ; c^, vesicula seminalis, or " cirrus pouch " ; 

 e, cirrus with vas deferens attached to its root; e', orifice 

 of cirrus canal ; /, vagina with canal ; ^, ductus eff erens 

 of same ; ^, receptaculum seminis filled with spermatozoa ; 

 z, fertilising canal making a junction with porose ovi- 

 duct ; J, porose oviduct ; h, aporose oviduct forming a 

 junction with j ; I, porose ovary ; m^ aporose ovary ; 

 n, yelk gland with its efferent duct ; o, shell gland ; 

 j), uterine canal. The ovaries, yelk gland and shell 

 gland should be nearer the receptaculum ; they have 

 been figured thus, although drawn to scale, to show 

 the probable course of the fertilising canal and oviducts. 

 X 62. 



Fig. 1 1 . Ripening segment, dorsal, a, uterine pouches containing 

 ova j 6, vaginal opening on proximal margin j c, distal 

 margin ; d, anterior margin ; e, posterior margin of 

 segment x 70. 



Figs. 12, 13, 14, 15, 16, successive stages in the development of 

 the oncosphere, x 350. 



Fig. 17. One of the six hooks of the oncosj^here, x 1400. 



