GUDE: ON NEW HELICOID LAND-SHELLS. 265 
types. The only question now remaining is whether Mousson’s 
Nanina pusilla is really identical with Pfeitfer’s species, a question 
which the diagnosis by Von Martens is insufficient to decide. That 
the shells now under consideration are really different from Pfeiffer’s 
types there is no doubt, and whether they pertain to Mousson’s species 
comparison only can decide. Since Mousson’s types are not accessible, 
I consider the most prudent course to pursue is to ignore Mousson’s 
name and to treat the present shells as belonging to an undescribed 
form. Von Martens has recorded for Jf, Jenynsi, in addition to Querimba 
Island and Mozambique, a number of localities in German East Africa." 
He also refers to the fact that the species occurs in Java and the 
New Hebrides, and is more or less restricted in East Africa to the 
coast district, so that, he thinks, an introduction from the East is 
not improbable ; although, as he continues, its close affinity to Dozam- 
bicensis, an inland species, is opposed to this theory. 
The differences between Xesta Dwipana and Martensia Jenynsi can 
best be given in tabular form :— 
Senynst. Dwipana. 
Shell. Thick, solid, opaque, yellowish | Thin,fragile,translucent, 
white. corneous. 
Spire. Elevated conoid. Depressed. 
Last whorl. | Keeled all round. Angular at first, rounded 
at the mouth. 
Base. Rounded. Swollen. 
Aperture. Crescent-shaped. Semi-rotund. 
Sculpture. Distinct spirals. Obsolete microscopic 
spirals. 
For better comparison I have added figures of JZ. Jenynsi from 
Mozambique (Pl. VII, Figs. 12-14). 
5. Guppya Furront, n.sp. Pl. VII, Figs. 18-20. 
Shell imperforate, conoid, pale corneous, ornamented above with 
transverse brown zones, finely striated, lustreless above, shining 
below. Spire conoid, suture margined, apex obtuse. Whorls 63, 
subplane above, tumid below, increasing slowly and regularly, last 
not dilated, not descending anteriorly, surrounded at the periphery by 
an acute, slightly exserted keel. Aperture nearly vertical, unevenly 
crescent-shaped; peristome thin, straight, acute; columellar margin 
slightly dilated. Diam. 5, alt. 3°5 mm. 
Hab.—Cocos Island, Pacific Ocean. 
Type in my collection. 
Two specimens were received from Messrs. Sowerby & Fulton as 
Guppya Hopkins’, Dall. Upon comparison with Dall’s description 
and figures? they proved to be different, and I was at first inclined 
1 Deutsch. Ost-Africa, Bd. iv (1897), p. 49. 
2 Proc. Acad. Nat. Sci. Philad., 1900, p. 97, pl. vii, figs. 5, 6. 
