32 MOLLUSCA. 
Helix calva, Goutp; Proceed. Boston Soc. Nat. Hist., 1.179. Noy. 
1846. Expedition Shells, 25. Premrrer; Monog. Helic. Viv., i. 41. 
Suet thin, depressed globose, highly polished, of a pale cinereous 
olive-colour, somewhat inclined to flesh-colour, paler beneath. Whorls 
five, not turgid above, but arranged so as to present a regular dome- 
shaped convexity, their boundary being faintly indicated by the double 
suture. The lines of growth are scarcely perceptible, except near the 
termination of the outer whorl. Beneath, this whorl is turgid, round- 
ing off into a very small, fissure-like perforation, in front of which is a 
slight reflection of the columellar portion of the lip. Aperture semi- 
lunar, the lip simple and very sharp. 
Diameter four-fifths of an inch; axis half an inch. 
Inhabits the Feejee Islands. 
Similar to H. durida, but smaller and lighter-coloured, and is plainly 
distinguished by its smooth, shining, rounded spire, similar to the 
summit of H. Moricandi or H. lychnuchus. This must also be a 
Nanina. The name originally applied by me having been preoccu- 
pied, I have substituted the present. 
Figure 69, the shell above; 69 a, the profile; 69 4, basal view. 
Nanina FRICATA (Gould). 
Testa rotata, tenuis, viridi-cornea, superne convextiuscula, hris crebris 
radiantibus interdum furcatis insculpta, inferne glabrata, umbilco 
lato, profundo, infundibuliformi perforata: spira anfractibus quatuor 
cum dimidio ; suiura impressa: apertura rotundata ; labro stmplict. 
SHELL rotate, thin, greenish horn-colour, a little convex above, and 
marked with rather crowded but distinct ridges in the direction of the 
lines of growth, many of which bifurcate towards the periphery, where 
the ridges disappear and leave the basal face polished, or reappear 
within the umbilicus; umbilicus large, penetrating to the summit and 
gradually decreasing with each whorl; aperture rather large, circular, 
except where interrupted by the penult whorl; lip simple: whorls 
