Alvania pinguis
Alvania pinguis is a species of small sea snail, a marine gastropod mollusk or micromollusk in the family Rissoidae.
Description
The length of the shell attains 2 mm, its diameter 1.25 mm.The white shell consists of 4½ rounded but slightly flattened whorls, of which a very glossy protoconch occupies the first one and a half.
Sculpture: Fine spiral lines, three on the third and four on the body whorl above the aperture. The spirals are crossed by close-set longitudinal ribs as strong as the spirals. They die out on a level with, the posterior angle of the aperture, and the base has three spirals only. The columella is vertically arcuated. The aperture is diagonal-oval, a little angled where the outer lip joins the columella, behind which is a deep groove. The
outer lip is thickened externally, especially where it joins the body whorl.