Physical Characteristics

The shell is very small, fragile, inflated, and almost semiglobu-lar and has a large, bulbous apex and flat peristome. The apex is mamillate and forms an angle of approximately 45° with the basal plane. Apart from occasional small pits, there is no distinct sculpture on the slightly worn apical area. Outside this area is a fine, irregularly concentric striation. In the furrows between the ridges are numerous small pits. The shell is unusually convex with the apex well in front of the anterior edge. The highest point of the shell is slightly anterior of center. No muscle scars can be discerned on the interior. The exterior layer of the shell does not contain defined prisms. The head is unusually large and bulging and has short, tapering, strongly ciliated velar lappets at the sides. The anterior lip seems to be very solid and cuticularized. Postoral tentacles are not present. The foot is round with a thickened rim. Three pairs of small, simple, tubercular gills are situated in the pallial groove and lack appendages. Five small, close-set muscle bundles are situated along the central third of the body halfway between the midline and the lateral margin.

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