ON AMPHILINA PARAGONOPORA 57 



the tip of the ductus is markedly thick and muscular, forming 

 a penis. There is no conspicuous cirrus sac and no penial setae. 



I will now hriefly note some differences which exist 

 between the genital system of A . p a, r a g o n o p o r a , as just 

 described, and the genital systems of A . f o 1 i a c e a , A . 1 i g u - 

 loidea, and A. magna, as described ])y authors already 

 named. All these three latter species are apparently distin- 

 guished from A . p a r a g o n o p o r a by the fact that the 

 vaginal aperture lies at a considerable distance apart from the 

 penial aperture: in A. foliacea it is separated by about 

 one-third the distance between the base of the ovary and the 

 end of the body, and is situated on the edge of the left side 

 (the ' right ' side of Salensky, who, according to my determina- 

 tion, viewed his specimens from the ventral surface) of the 

 body; in A. ligu loidea it is separated by about three- 

 quarters of this same distance, and, according to Janicki, is 

 paired ■*• — one opening being median and ventral and the other 

 median and dorsal ; in A . magna Southwell figures the 

 vaginal aperture as being separated by about one-fifth of this 

 same distance, and hes in the middle line and it presumably 

 opens dorsally. 



In A . foliacea the posterior half of the vagina lies to the 

 left of the ductus, but in the other three species the whole of 

 the vagina lies to the right of the ductus. In A. foliacea 

 the cirrus sac is not terminal but lies midway between the 

 ovary and the opening ; in A . 1 i g u 1 o i d e a the sac is figured 

 as terminal; in A. paragonopora there is no distinct 

 cirrus sac. Only in A. foliacea are there penial setae in 

 connexion with the very long penis (setae and length correlated 

 with the lateral situation of the vagina and the distance 

 separating the two openings?). In A. liguloidea alone 

 the vagina carries an anterior blind diverticulum extending 

 anterior to the ovary — the so-called ' anterior vagina '. The 

 testes are stated to be scattered in A. foliacea but in the 

 other three species ' they are linear in arrangement, lying just 



^ Monticelli only describes a single aperture. 



^ Southwell states that the testes are ' scattered about through the 



