from the Malay Archipelago. 417 



(19) Planorbis {Gyraulis) elberti, sp. n. 



Shell discoidal, rather thin, semitransparent, pale horn- 

 colour ; spire somewhat concave; whorls 5^, rapidly in- 

 creasing, densely striated, the last obtusely carinated at its 

 periphery ; suture deeply impressed ; base of shell concave; 

 aperture somewhat rhomboidal, a little broader than high, 

 rounded above and below, angulated laterally ; peristome 

 thin, acute. 



Diara. maj. 7*5, diara. mln. 6*5 ram. ; alt. 1*75 mm. 



Type locality. Swamps of Sembaloen Plain, Lombok ; some 

 more specimens from Sadjang, Lombok. 



Specimens examined 47. 



(20) Cyclotus discoideus, sp. n. 



Shell very depressed-conic, nearly discoid, widely umbili- 

 cated, solid, faintly and densely striated above and below, 

 pale horn-colour, marbled with dark brown, and with a 

 narrow dark subperipheral band ; apex obtuse ; whorls 4^, 

 regularly increasing, the last slowly descending anteriorly ; 

 suture well impressed ; aperture circular, somewhat oblique ; 

 peristome double, the iinier margin simple, the outer thickened 

 and somewiiat expanded. 



Diam. maj. 18o, diam. min. 15 mm. ; alt. 11 mm. 



Type locality. Kabaena Island, off S.E. Celebes. 



Specimens examined 17. 



(21) Cyclophorus ivetaranus, sp. n. 



Shell somewhat depressed-conic, umbilicated, solid, very 

 faintly striated above, nearly smooth below, pale to dark 

 horn-colour, with very indistinct darker markings and a 

 narrow dark subperipheral band; apex obtuse; whorls 5, 

 regularly increasing, the last swollen, somewhat descending 

 anteriorly ; suture distinctly impressed ; aperture circular, 

 somewhat oblique ; peristome somewhat thickened, slightly 

 expanded, with a slight whitish callus inside. 



Diam. maj. 14, diam. min. 11 mm. ; alt. 11*5 mm. 



Type locality, llwaki, Wetar ; other locality, Tihoe, 

 Wetar. 



Specimens examined 9. 



{22) Lagochilus tricarinafus, sp. n. 



Shell conic, umbilicated, solid, with a strong peripheral 

 and a faint keel both above and below it, finely striated, horn- 



