1863. ] Contributions to Indian Malacology. 321 
culum, but have restricted it to the only species hitherto described 
as possessing a tube, viz. Sp. hispidum,* (Pterocyclos hispidus). The 
discovery of a second species shews that this separation is justified. 
The genus is distinguished from Péerocyclos both in the possession 
of this small tube, which recalls the same process in Optsthoporus 
Bens. and also in the absence of the “wing” or cowl-shaped free 
process of the outer lip in the peristome of Pterocyclos, which is 
represented by the small linguiform projection of Spiraculum. 'There 
also appears, if the character of the mantle of Sp. Avanum prove 
constant, to be a distinction in the animals; for although several 
species of Pterocyclos have been carefully examined, no peculiarity 
in the animal has been found to correspond to the singular formation 
of the peristome, while in the present species of Spzraculum there is 
a deep notch in the mantle, corresponding to the tube in the shell. 
A third and very singular species of Spiraculwm exists in Assam, 
but has not yet been described J am disposed to consider the ge- 
nus as forming an important link between the Oyclophoride, certain 
forms of the Pupinidw, and the aberrant genus Alyceus. 
The present species is distinguished from Sp. hispidum, Pearson, by 
its smaller size, by the epidermis being only slightly rough, instead 
of hairy, and by the sutural tube being nearer the mouth, and bent 
backwards in the form of an arch. The projection of the outer lip 
near the suture is vertical instead of horizontal. The operculum is 
far flatter, resembling in this character, that of the Burmese species 
of Pterocyclos e. g. Pt. pullatus, Bens. 
2. CYCLOPHORUS HISPIDULUS, Nn. s. 
Shell widely umbilicate, subplanulately depressed, radiately striated 
and marked by extremely fine and close concentric impressed lines, 
white, covered with a thick dark brown epidermis, which forms a broad 
raised spiral costulation around the shell, more marked in young than 
in fully grown specimens. Spire almost flat, apex just exserted, 
suture deep. Whorls 5, cylindrical, the last descending very little 
near the aperture, which is subvertical and circular. Peristome 
double, inner lip continuous and projecting a little; outer lip slightly 
expanded. Operculum multispiral, externally flat, the margins of the 
* Gen. Rec. Moll., H. and A, Adams, Vol. II. p. 278, the following is the 
description given, “Shell with a reverted, closed tube or spiracle, situated on 
the suture near the aperture.” The tube is not closed however, but open, the 
interior aperture being more or less in the form of a longitudinal slit. 
Sie 
