This is a fresh-water shell, found in the lakes of Europe.
Shell thin and brittle, obliquely conical; summit pointed and recurved;
margins simple, base oval and smooth.
Ancylus oblongus.
Ancylus fluviatilis.
_A. oblongus._ The oblong Ancylus.
Aperture elongated, vertex turned to one side, striated concentrically;
exterior pale yellowish colour, interior light blue.
_A. fluviatilis._ The river Ancylus. Pl. 32, fig. 3.
Simple, oval, almost symmetrical; summit pointed, compressed, very
distinct; bent back a little to the right, but not marginal; the edges
of the aperture entire and effuse.
FAMILY IV.
BULLACEA. Three genera.