99 



Za 



Lacuna carinifera, A. Adams. L. testa ovatii, spird acuminata, 

 anfractibus quatuor, late umbilicatd, fulvd, anfractu ultimo 

 angulato, carina transversd elevatd, rufo-fusco articulatd, or- 

 nato ; aperturd semiovatd ; labro acuta, angulato, labio recto, 

 fissurd uinbilicali elonyatd. 



Hah. Borneo. Mus. Cuming. 



The single prominent keel round the periphery of the last whorl 

 is the principal feature of this species. 



Velutina Sitkensis, a. Adams. V. testa nigro-fuscd, epider- 



mide liris elevatis transversis confertis obtectd, longitudinali- 



■ ter valde sulcatd, sulcis subdistantibus ; aperturd ovali, intus 



sulcatd; labro margine rejlexo, nigra, incrassato ; postice nan- 



praducto supra anfractum ultimum. 



Hab. Sitka. Mus. Cuming. 



The dark brown colour and oval form distinguish this species from 

 V. Icevigata, which also has the outer lip arched and expanded poste- 

 riorly. 



Otina fusca, a. Adams. O. testa magnd, solidd, semiopacd, 

 fused, sine epidermide, dorso convexd, longitudinaliter subpli- 

 catd, transversim tenuiter striatd, labio lata, plana, et exca- 

 vato ; labra recto, non rejlexo aut expanso. 

 Hab. Benguela. Mus. Cuming. 



The large size of this species, and its convex form, distinguish it 

 from O. Otis, and its absence of bands, and the outer lip not being ex- 

 panded, from O. zonata, Gould, the only two species at present known 

 to me. 



7. Note on Nematura, by A. Adams. 



The genus Nematura, established by Mr. Benson, appears to have 

 the closest affinity with Bithynia of Leach, but the horny opercu- 

 lum, with grooved margins, and the contraction of the aperture, will 

 distinguish them. There appear to have been found at present but 

 six species, three of them known, and three here indicated for the 

 first time ; in the rivers and streams of the East are doubtless many 

 more ; they are usually found adhering to the under surface of dead 

 floating leaves. 



1. Nematura Delt^, Benson. N. testd magnd, pallide fulvd, 

 globosd, Icevi ; aperturd orhiculari, peritremate sitnplici. 



Mus. Cuming. 



2. Nematura minima, Benson. N. testd parvd, corned, semi- 

 pellucidd, ovali, spird subproductd ; politd, fasciis rujis sub- 

 obsoletis ornatd ; aperturd orbiculuri, peritremate sitnplici. 



Mus. Cuming. 



No. CCXXXIIL — Proceedings of the Zoological Society. 



