TERRESTRIAL MOLLTTSCA INHABITING SOCIETY ISLANDS. 
21 
M. scALPTA, Garrett. Plate II, figs. 30, 30 a, 30 b. 
Shell imperforate, orbicular, depressed, thin, smooth, subpellucid, very glossy; 
fulvous, minutely dotted and irregularly lineated with whitish radiating lines ; spire 
convex, moderately elevated ; suture rather faintly impressed ; whorls five, flatly 
convex, moderately increasing, last one rounded, not deflected in front ; base convex, 
indented at the axis ; aperture nearly vertical, orbicular-lunate ; peristome straight, 
thin, regularly curved, margins remote ; columellar region thickened with callus. 
Major diam'. 10, height 6 mill. 
Hah . — Tahaa Island. 
This fine species occurs plentifully in a small area in Ilaamene valley on the east 
of Tahaa. They were gregarious beneath stones, rotten wood, and under heaps of 
decaying leaves. Not a single example taken in any other part of the island or group. 
It is the same size as simllliina, but may be distinguished by its more solid texture, 
darker color, more elevated spire, deeper body-whorl, more rounded ap(uture, and the 
whorls are flatter and more tightly coiled. The peculiar pale markings which 
suggested the specific name appear very much like scratches on the surface of the 
shell. 
Genus TROCHONANINA, Mousson. 
In 1869, Prof. Mousson established the genus or subgenus Trochonanina (Jour, de 
Conch., p. 329), for the reception of the Polynesian trochiform or conical Nanime, the 
type of which is N. ^JimeUziana. Mr. Pease injudiciously classed it witli Trocho- 
morpha, and Helix conula, Pse., which is precisely the same type he places in the 
genus Helicopsis = Microcystis. 
I fully share Mousson’s views in regard to the propriety of eliminating this group 
from the typical Microcystis. They differ from the latter genus in the more or less 
elevated-conical or trochiform shape, angidated or filocarinate periphery, closed or 
perforated base, and subrhomboidal luniform aperture. Like the preceding genus, the 
columella is either simple, nodulous or spirally plaited. The base is always smooth 
and shining; the superior surface is rougher, the strice more decided and regular, 
sometimes rib-like, and frequently with fine spiral raised lines. 
They possess the habits of Microcystis, and, except the Sandwich Islands, where 
they appear to be absent, have nearly the same distidbutiou. 
T. CONULA, Pease. Plate II, figs. 30, 36 o, 36 h. 
Helix conula, Pease, Proc. Zool. Soc., 1861, p. 243. Pfeiffer, Mon. Hel., v, p. 62. 
Helicopsis conula. Pease, Proc. Zool. Soc., 1871, p. 475. 
Nanina Tongana, Schmeltz (not of Qiioj' and Gainiard), Cat. Mus. Godeff., v, p. 01 (“sec 
Mousson 
Microcystis conula, Garrett, Jour. Acad. Nat. Sci. Pliila., 1881, p. 383. 
Rather plentiful ou the foliage of low bushes and common to all the islands. It 
occurs, also, at Rarotonga, one of the Cook’s or Harvey Islands. 
4 
JOUE. A. N. S. PHILA.,VOL. IX. 
