RISSOLD A. 265 
t 
As yet only known fossil in tertiary deposits. &. variculosa, 
Desh. (1xxii, 50). 
Nevituia, H. Adams. 
Dedicated to Mr.Geoffrey Nevill,an Anglo-Indian conchologist. 
Distr.—2 sp. Mauritius, Isle of Bourbon. N. picta, H. Adams 
(Ixxi, 52). 
Shell imperforate, acutely ovate; whorls convex, spirally 
lirate, longitudinally striate; aperture oval; columella callous, 
toothed ; lip acute, smooth within, varicose outside. 
This genus has much the appearance of a minute species of 
Craspedotus, but there is no indication of nacre within the aper- 
ture, and the tooth on the columella is more like that of Rissoa 
monodonta ; in form and sculpture Nevillia approaches Alvania. 
PurILuA, A. Ad., 1867. 
Disir—P. lucida, A. Ad. (Ixxii,51). Japan. 
Shell turbinately conoidal, solid, smooth, rimate; aperture 
suborbicular; lip thickened, subeffuse in front, scarcely ex- 
panded. Family relationship obscure. 
SusraMity HYDROBIINZ. 
Shell very small, or of moderate size, never exceeding two- 
fifths of an inch in length, globose, ovate, or elongated, generally 
umbilicated or rimate, and covered with a periostraca for the 
most part of an olive-color; whorls moderately numerous (4-8), 
smooth, or, rarely, ribbed or carinated, never cancellated ; aper- 
ture more or less ovate or rounded, rarely subacute or effuse 
anteriorly ; peritreme continuous; outer lip usually simple and 
acute. Operculum paucispiral, corneous. ‘Tentacles, verge and 
gills as in the diagnosis of the family (p. 259). Foot without 
lateral sinuses, truncate and auricled in front, and generally 
rounded behind ; operculigerous lobe destitute of cirri. Station, 
in fresh and brackish water. 
Like all of the Rissoidz these little animals are strictly her- 
bivorous. Moquin-Tandon remarks that they have, connected 
with the stomach, a cartilaginous stylet like that occurring in 
certain bivalves. Something like this stylet Stimpson has 
observed also in our American Melanians. 
LitrTorINeLLA, Braun. 
Syn.—Paludinella, Lovén (not Pfeiffer). Littorinidea, Eyd. 
and Soul. 
Distr.—W orld-wide, brackish or sea-water, in sheltered posi- 
tions. L. minuta, Totten (1xxii, 53). 
Shell ovate or elongated, thin, smooth, perforate; whorls 
ventricose; apex obtuse; aperture rather broadly oval; inner 
lip not thickened. Operculum corneous. 
18 
