20 'fERKESTlilAL MOLLUSOA INHABITING SOCIETY ISLANDS. 
by tlic gno periphery-kecl. Tl.e beautiful oblique striiO are congnecl to tl.o upper surface, 
tbe lower being smooth and more glossy. The axis is more or less dtstmctly punctate. 
The sliL'htlv oblique aperture is angulate-lunate. 
Tlie crmvded, regular, raised strife and delicate filiform keel will at once distin- 
guish it. 
M. DiscordIsE, Garrett. Plate II, figs. 35, 35 a, 35 b. 
Microcystis Discordise, Garrett, Jour. Phil. Acad. Nat. Sci., 1881, p. 383. 
Nanina subtilis, Schmeltz (not of Anton), Cat. Mus. Godeff., v, p. 91. 
Abundant under damp rotten wood, and ranges throughout the group. It is 
equally as common at the Cook’s or Harvey Islands. A few specimens were taken by 
me at the Marquesas group. 
A small, fragile species, about the size of normalis, with a more or less distinctly 
aiigulate body-whorl, smooth upper surface and lighter colored than the latter. 
M. CULTR.ATA, Goulcl. 
Helix cultrata, Gould, Proc. Post. Soc. Nat. Hist., 1846, p. 172; Expl. Ex. Shells, p. 46, fig. 
59. Pfeiffer, Mon. Hel., i, p. 37 ; {JErepta) Vers., p. 128. 
Sagda cultrata (Gastrodon), H. and A. Adams, Gen. Moll., ii, p. 113. 
Xanina cultrata, Gray, Cat. Pulm., p. 130. (Microcystis) Albers, Ilel., p. 49. Bland & 
Binney, Anier. Jour. Conch., 1871, p. 189 (dentition). 
llelicopsis cultrata, Pease, Proc. Zool. Soc., 1871, p. 475. 
In 1862, I found examples of this species amongst decaying vegetation in Taliiti, 
but cannot state the precise locality. 
It is a depressed, orbicular, very shining species, 6 mill, in diameter, with five 
whorls, the last one carinated and the columella dentated. 
.AI. ANGUSTIVOLUTA, G.arrett. Plate II, figs. 34, 34 a, 84 b. 
Sliell small, orbicular, depressed, imperforate, thin, smooth, shining, pale amber- 
color, with or without small, irregular opaque-white spots ; spire convex, apex 
depressed; suture laintly impressed, narrowly margined; tvhorls 5|-6, subplaniform, 
narrow, slowly and regularly increasing, last one dej)ressed, not descending in front, 
periphery subangulate ; base flatly convex, deeply indented at the axis ; aperture 
nearly veitical, ver\ narrow, luniform, much wider than deep; peristome thin, simple, 
witli very remote margins ; columella small, very oblique. 
jSIajor diam. 4|, lesser diam. 4, height 2^ mill. 
Hah . — Moorea Island. 
A few examples were found under damp rotten wood on the northeast part of the 
island. 
Its most obvious characters are its depressed form, numerous, narrow whorls sub- 
angulate periphery, narrow aperture and indented base. 
