Aulopoma
Aulopoma is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Cyclophoridae. They are endemic to Sri Lanka.
Four species are recognized.
General characteristics
The operculum perfectly resembles the shell of a Planorbis; it consists of many slowly widening whorls that enclose an internal spiral cavity. On the body whorl a circular groove runs inward, which receives the simple peristome of the shell. Consequently, the edge of the operculum overlaps the margin of the shell aperture like the lid of a jar. The simple peristome does not lean against the previous whorl — a necessary feature to allow the operculum to overlap — which provides a means of distinguishing this genus from other cyclostomids even in the absence of the operculum.The shell of the single species upon which I establish this interesting genus was collected in Ceylon by my unfortunate friend Dr. Hofmeister, who sadly passed away during his travels. In memory of its discoverer, I name it A. hofmeisteri. It is flat, almost disc-shaped, with a slightly projecting, very pointed spire, deeply impressed sutures, and a wide umbilicus. It is yellowish in color with brown bands and markings. Its diameter is 8 mm.
The shell is low-turbinate to disc-shaped, with the body whorl detached at the front. The peristome is free, straight, and continuous, fitting into a circular groove on the operculum. The operculum itself is not calcified and is slightly larger than the aperture; it is tightly coiled, planorbiform, and composed of two lamellae. Between these lamellae lies a spiral canal, while the outer edge features a groove designed to receive the peristome.
Species
Aulopoma grande Pfeiffer, 1855Aulopoma helicinum Aulopoma itierii Guérin-Méneville, 1847Aulopoma sphaeroideum Dohrn, 1857;Synonyms:Aulopoma hofmeisteri Troschel, 1847 : synonym of Aulopoma itierii Aulopoma itieri : synonym of Aulopoma itierii Aulopoma lowi de Morgan, 1885 : synonym of ''Platyrhaphe lowi''