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Lacuna CARINIFERA, A, Adams. L. testd ovata, spird acuminatd, 
anfractibus quatuor, late umbilicatd, fulvd, anfractu ultimo 
angulato, carind transversd elevatd, rufo-fusco articulatd, or- 
nato; aperturd semiovatd ; labro acuto, angulato, labio recto, 
Jissurd umbilicali elongatd. 
Hab. Borneo. Mus. Cuming. 
The single prominent keel round the periphery of the last whorl 
is the principal feature of this species. 
Vexutina Sirxensis, A. Adams. JV. testd nigro-fused, epider- 
mide liris elevatis transversis confertis obtectd, longitudinali- 
ter valde sulcatd, sulcis subdistantibus ; aperturd ovali, intus 
suleatd ; labro margine reflexo, nigro, incrassato ; postice non- 
producto supra anfractum ultimum. 
Hab. Sitka. Mus. Cuming. 
The dark brown colour and oval form distinguish this species from 
V.. levigata, which also has the outer lip arched and expanded poste- 
riofly. 
Otrna Fusca, A. Adams. O. testd magnd, solidd, semiopacd, 
Sused, sine epidermide, dorso convexd, longitudinaliter subpli- 
catd, transversim tenuiter striatd, labio lato, plano, et exca- 
vato ; labro recto, non reflexo 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 Nemartura, sy 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 aré usually found adhering to the under surface of dead 
floating leaves. 
1. Nematura Detts, Benson. N. testd magnd, pallidé fulvd, 
globosd, levi; aperturd orbiculari, peritremate simplici. 
Mus. Cuming. 
2. NEMATURA MINIMA, Benson. WN. testd parvd, corned, semi- 
pellucidd, ovali, spird subproductd ; politd, fasciis rufis sub- 
obsoletis ornatd ; apertura orbiculuri, peritremate simplici. 
Mus. Cuming. 
No. CCXXXIII.—Procrepincés or THE ZOOLOGICAL SOCIETY. 
