302 MR WALTER E. COLLINGE ON THE 



3. Wiegmannia ponsonbyi, n. sp. 

 PI. I. figs. 9, 10 ; PL II. figs. 29, 30. 



Animal yellowish-brown, with few, almost black, blotches and spots. Head 

 almost black ; lateral grooves and median line of rugae well marked. Mantle same 

 colour as body, comes upon all sides of the visceral mass, and has a thin shell- 

 border and fairly well-developed keel. Extremity of foot truncate. Posterior 

 portion of dorsum bluntly keeled. Rugae faintly marked. Sulci blackish. Caudal 

 mucous pore a longitudinal vertical slit extending to the foot-sole. Peripodial groove 

 prominent. Foot-fringe same colour as the body ; lineoles black. Foot-sole almost 

 black anteriorly, posteriorly same colour as the body ; divided into median and 

 lateral planes. 



Length (in alcohol) 42 millim. 



Shell same as in W. gigas, only smaller and reddish-brown in colour. 



Hab. — Kuching, N.W. Borneo. 



Generative Organs. — (PI. II. figs. 29, 30.) 



The external form of the penis differs considerably from that of W. gigas or 

 W. dubius, Wgm. ; it is much shorter and is not folded to anything like the same 

 extent. From the vestibule as far as the diverticulum it is uniform in circumference ; 

 opposite the diverticulum there is a small retractor muscle inserted. The distal 

 portion of the penis gradually tapers, giving place to the vas deferens (PL II. fig. 

 29). The receptaculum seminis is small, somewhat pear-shaped, and opens into the 

 right side of the vagina. This latter organ is much longer than in the preceding 

 species and exhibits a slight constriction just beyond its anterior third. The free- 

 oviduct, on the other hand, is very short. The dart-gland is similar to that in W. 

 gigas, only larger and not so uniform in shape, exhibiting a series of constrictions 

 and dilatations in the anterior (PL II. fig. 29, d.s.). Structurally the dart 

 is the same as that in W. gigas, but in this species the one present was much 

 more fragile, and a little over twice the length of that found in the preceding 

 species (PL II. fig. 30). 



4. Wiegmannia borneensis, n. sp. 



PL I. figs. 11, 12 ; PL II. figs. 31, 32. 



Animal brownish-yellow with faint blackish mottling on the fore part of the 

 head and dorsum, lateral grooves and median line of rugae well marked. Mantle 

 same colour as body with dark mottling ; comes upon all sides of the visceral mass ; 

 has a thin shell-border ; keel more conspicuous posteriorly. Extremity of foot 

 truncate. Posterior portion of dorsum keeled. Rugae large. Sulci sepia coloured. 

 Caudal mucous pore a vertical slit extending to the foot-sole. Peripodial groove 



