I .,'1 

 Rissoia Fréminville. 



i . Rissoia sp. 



Stat. 285. Soutl I rimor. $4 M. On the limit betwcen mud and coral. I.ithothamnion. 



1 S 



Having much resemblance with the description and figure of A'. venusta Garret, by its 

 shape and sculptu isisting of strong, compressed, spiral ridges, of which 2 on the upper 



whorls, 5 on the body whorl and conspicuous radiating riblets; but the shell is smaller, there 



.1 few secundary spirals, especially on the body whorl and the lip is not varicose; as it 

 is however very thin and fragile, the specimen may l>e juvenile. l'nder these circumstances, I 

 am not able to identify this single specimen, nor to describe it as new with a sufficiënt degree 



rtainty. 



2. Rissoia kwandangensis n. sp. PI. XII, hg. 9. 



Stat. 115. Kast side of Pajunga-island, Kwandang-bay, North Celebes. Reef. 1 Spec. 



Shell small, conic-oval, solid, opaque: whorls about 6, slightly convex, separated by a 

 deep suture, colour whitish, with spiral rows of purple-brown spots. Nuclear whorls smooth, 

 sculpture of subsequent whorls consisting of rather thin, straight ribs, about iS on the last 

 whorl, crossed by spiral ridges, of which there are 6 on the penultimate whorl and 11 on the 

 last one, the sixth running just in a channel above the suture-, this sculpture renders the shell 

 cancellated; moreover fine growth-striae make their appearance in the squares remaining in the 

 interstices of this sculpture. Of the brown spots the upper spiral row runs a little below the 

 suture, on the alternating ribs, and five fainter ones, on the basal part of last whorl. Aperture 

 rounded oval, slightly angular above, outer margin regularly curved, with a strong varix externally; 

 columellar margin reflected over the pillar and the base. Yarix adorned with two larger brown 

 spots, one at the upper and one at the basal part. 



Alt. 2 1 /,, lat. i 1 /,; apert. alt. '/,, lat. '/. Mill. 



This small species is allied to R. versoverana Melv. (Mem. Manch. Philos. Soc, VII, 

 1893, p. 6 1 but that species is much more ventricose. 



Fam. Hydrobiidae. 

 Bithynia Leach. 



1. Bithynia truncata Eydoux «S: Souleyet. 



Eydoux & Souleyet. Vby. de la Bonite. Zool. Vol. II, p. 348, PI. 31, tig. 22 — 24. 

 v. MARTENS. Süss- u. Brackw. Moll. Ind. Arch. p. 25, PI. 9, fig. 11, 11/». 



Stat. 4. Rivulet near Djangkar (Java). 2 Spec. 



.SS 



