COLLECTED IN DUTCH iNTEW GUINEA. 



299 



pattern. The remnants of a periostracum are visible at the sutures and elsewhere. 

 The colour is dull ochreous above the carina, which is faintly suffused with brown, and 

 exhibits a white edge. Below the carina it is pale and colourless. The columella is 

 broad and reflexed over the umbilicus, which is, however, not entirely covered over by 

 it. The aperture is rounded, and the inferior lip reflexed. 



Dimensions : alt. 10 mm., width 14'5 mm., width of aperture 7 mm. 



B. Internal Characters. 

 Within the mantle-cavity the pneumostome (PI. XXXIII. fig. 3) calls for attention. 

 The actual orifice is situated in the middle of a modified portion of the floor of the 



pn- 



Fapuina ivolJustoni, geiiitalia. pe., penis ; pm., penis retractor ; ep., epiphallus ; fl., flagellum ; W., vas 

 deferens ; cl., common genital aperture ; v., vagina ; sptJi., spermatbeca ; od., oviduct ; ag., albumen 

 gland ; below ag. is seen the hermaphrodite duct. 



cavity. This area is circular in shape, and divided into tAvo unequal parts by a groove 

 which widens at one end to form the actual orifice, the two parts thus separated 

 being probably capable of divarication one from another to increase the diameter of 

 the respiratory aperture. One of these two lobes or fiaps is continuous with the floor 

 of the chamber, while the other is wholly separated from it by a shallow groove. 



Thejaio (PI. XXXIII. fig. 5) is thin and rather weak, with no transverse ribbing 

 and with a marked median protuberance. 



