22 TERRESTRIAL MOLLUSCA INHABITING SOCIETY ISLANDS. 
Its trochiform shape, acutely angular body, and conspicuous peculiar columellar 
plait, will determine it. 
T. opcontca, Pease. Plate II, figs. 37, 37 a, 370. 
Helix obconica, Pease, Proc. Zool. Soc., 1864, p. 669. Pfeiffer, Mon. Hel., v, p. 85. 
Trochomorpha obconica, Pease, Proc. Zool. Soc., 1871, p. 475. 
Nanina obconica, Schmeltz, Cat. Mus. Godeff., v, p. 207. 
This species is peculiar to Raiatea, where it is very local and somewhat rare. It 
occurs in the higher portions of two valleys, one on the east and the other on the 
west side of the island. 
Its most essential characters are its depressed-trochoid form, acute carination, small 
but pervious umbilicus, and fine crowded strive. My largest example is 8 mill. in 
diameter. 
T. caALcuLosa, Gould. 
Helix calculosa, Gould, Expl. Ex. Shells, p. 48, Pl. V, fig. 63. Pfeiffer, Mon. Hel., iii, p. 41. 
Zonites (Conulus) caleulosus, H. and A. Adams, Gen. Moll., ii, p. 116. 
Nanina calculosa, Gray, Cat. Pulm., p. 126. Schmeltz, Cat. Mus. Godeff., v, p. 91. 
Nanina (Trochomorpha) caleulosa, Albers, Hel., p. 60. 
Not uncommon on foliage and is diffused throughout the group, ranging from the 
lowlands near the seashore to about 1000 feet above sea-level. I also obtained many 
examples on Dominique, one of the Marquesas Islands, and a few at Malolo, one of the 
Viti group. Its existence in the latter location is the more remarkable as it has not 
been observed on any of the intermediate islands. 
My largest examples, which are 44 mill. in diam., and a trifle less in height, are 
larger than Gould’s specimens. It may readily be distinguished by its globose- 
pyramidal form, angulate body-whorl and oblique aperture. ‘The umbilicus, though 
generally closed, is sometimes punctiform, and the columella reflexed. 
It is not included in Mr. Pease’s List of Polynesian Land Shells. 
T. suBruGosA, Garrett. Plate II, figs. 38, 38 a, 38b, 38 c, 38d. 
Shell small, imperforate, globose-conic, thin, subpellucid, fulyous; upper surface 
with crowded, slightly oblique, plicate strive; spire depressed-conic, apex planulate ; 
suture linearly impressed ; base convex, smooth, glossy, indented at the axis; whorls 
4-43. strongly convex, slowly and regularly increasing, last one narrow, rounded, not 
descending in front, periphery with a thread-like keel; aperture slightly oblique, 
transversely ovate-luniform; peristome thin, simple, regularly curved, with remote 
margins; columella slightly thickened with callus. 
Major diam. 24, height 2 mill. 
Hab.—Tahiti and Moorea. 
This small sculptured species is somewhat rare. It was found under stones on the 
northwest side of ‘Tahiti, at an elevation of about 1000 feet. A few examples were 
