100 TERRESTRIAL MOLLUSCA INHABITING SOCIETY ISLANDS. 
S. cosrata, Pease. 
Hydrocena costata, Pease, MS. Coll. Pease, 1863. 
Hydrocena Taheitensis, Carpenter (not of Pease), Proc. Zool. Soc., 1864, p. 676. 
Realia (Scalinella) costata, Pease, Amer. Jour. Conch., 1867, p. 216. 
Scalinella costata, Pease, Jour. de Conch., 1869, p. 158, Pl. VII, fig. 2. Schmeltz, Cat. Mus. 
Godeff., v, p. 102. 
Realia costata, Pfeiffer, Mon. Hel., iv, p. 216. 
Very numerous on the ground in the lowland forests of Tahaa, where it is 
peculiar. It differs from Tuheitensis in its larger size, more robust form, more turgid 
body, and the ribs are more numerous. 
S. Moussonr, O. Semper. Plate III, fig. 71. 
Taheitia Moussoni, “O. Semper,’ Schmeltz, Cat. Mus. Godeff., v, p. 102. Pfeiffer, Mon. 
Pneum., iv, p. 21 (name only). 
Not uncommon, and confined to the small island of Maupiti, where they occur on 
the ground in forests. 
The above name appears without description. I describe it as follows :— 
Shell rimate, rather slender, elongate conical, rather thick, cinereous, beneath a 
brownish or olivaceous epidermis; aperture rarely yellowish ; spire elongate, obtuse, 
with subplanulate outlines; whorls six and a half, strongly convex, apical ones smooth, 
the others with crowded, longitudinal ribs, about thirty on the rounded body-whorl ; 
aper'ure roundly ovate, vertical, nearly a third the length of the shell; peristome 
continuous, somewhat patulous, adhering to the penultimate whorl. 
Length 5, diam. 2 mill. 
More slender and smaller than Twheitensis, riblets more crowded and more 
numerous, body smaller and the aperture generally more oval. 
Genus HELICINA, Lamarck. 
H. Mavcert®, Gray. Plate III, figs. 64, 65, vars. 
Helicina Maugerix, Gray, Zool. Jour., i, p. 251; Beech. Voy., Bil XGXSeVI, fic: 26: 
Sowerby, Thes. Conch., Pl. III, fig. 55. (Zmoda) H. and A. Adams, Gen. Moll., ii, p. 
304. Pfeiffer, Mon. Pneum., i, p. 348. Mart. and Lang., Don, Bism., p. 61, Pl. III, fig 
22. Pease, Proc. Zool. Soc., 1871, p. 476. Schmeltz, Cat. Mus. Godeff., v, p. 99. 
This large and beautiful species is very plentiful on the trunks of trees and low 
bushes, and is confined to the upper parts of the valleys on the east and west sides of 
Raiatea, but is not found on the north and south portions of' the island. 
The type is white, rarely lemon-yellow, with a dark red dorsal and basal band, and 
saftron-yellow callus. The following varieties occur :— 
a. With two narrow reddish dorsal lines, with or without the basal band. 
b. Excepting the basal callus, uniform white. 
ec, Uniform lemon-yellow 
d. White, with reddish spire. 
All the above varieties are found associated with the type. Operculum pale 
amber-color. 
