196 

 Rissoia FreminviUe. 



I. Rissoia sp. 



Stat. 285. South coast of Timor. 34 M. On the Hmit between mud and coral. Lithothamnion. 

 I Spec. 



Having much resemblance with the description and figure of R. vemista Garret, by its 

 shape and sculpture, consisting 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 

 are a 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 be juvenile. Under these circumstances, I 

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

 of certainty. 



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



Stat. 115. East side of Pajunga-island, Kwandang-bay, North Celebes. Reef, i 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 18 on the last 

 whorl, crossed by spiral ridges, of which there are 6 on the penultimate whorl and 1 1 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. Varix adorned with two larger brown 

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



Alt. 2 7„, lat. 17^; apert. alt. 7,, lat. 7, Mill. 



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

 1893, p. 61) but that species is much more ventricose. 



Fam. Hydrobiidae. 

 Bithynia Leach. 



I. Bithynia trimcata Eydoux & Souleyet. 



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

 V. Martens. Siiss- u. Brackw. Moll. Ind. Arch. p. 25, PI. 9, fig. 11, ik^. 



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



