Manchester Memoirs, Vol. xlvii. (1903), No. 5. 7 



copulatrix, which cannot be homologized with that found 

 in the true Planocera. In fact, not only is it impossible 

 to derive the type of structure found in the female 

 apparatus of Paraplanocera from the type found in 

 Planocera, but it further seems impossible to suppose that 

 they can have been derived from a common primitive 

 type. On the other hand, the fairly close resemblance 

 that exists between the no less complicated male organs 

 of the same two genera obliges us to assume that a real 

 relationship exists between them. 



Amongst other Polyclads, a bursa copulatrix similar 

 to that found in Paraplanocera only exists in Eustyloc/ms, 

 a new genus founded by Verrill for StylocJius ellipticns 

 (Gerard) [6]. Verrill believes that a similar organ exists 

 in Stylochoplana maculata (Ouat.), for which species he 

 proposes a new genus, Heterostylocliiis, but an examina- 

 tion of de Quatrefage's account and beautiful figure of the 

 anatomy of this species makes it clear to me that the 

 median forwardly-directed vesicle of this species, which 

 lies over the penis, is rather to be compared to the vagina 

 and accessory vesicle (which in Paraplanocera I term the 

 receptaculum seminis), as the oviducts open into it. Con- 

 sequently, this organ is quite distinct from the bursa 

 copulatrix of Paraplanocera and from the organ which 

 Verrill regards as a " spermatheca," or seminal receptacle, 

 in Enstylochus. The latter genus can be readily dis- 

 tinguished from Paraplanocera by its styliform penis and 

 by the possession of marginal eyes. 



Family LEPTOPLANID/E. 

 Leptoplana pardalis, Laidlaw. 

 Five specimens from Funafuti. 



Family LATOCESTID^, nov. 

 Von Flehn [4] has not, I believe, commented on the 



