Distinguished from the Natica by the great width of the aperture, and
its short spiral columella.
Shell oval, more or less thick, very depressed, spiral short, little
elevated, lateral; aperture very extended, entire, the left edge
reflected and sharp; two lateral muscular impressions very disunited.
Sigaretus Haliotoideus.
S. convexus.
S. lævigatus.
S. cancellatus.
_S. convexus._ The convex Sigaretus. Pl. 22, fig. 2.
Very thin, smooth, back convex, spire white, rather prominent; aperture
very expanded; umbilicus rather deep; yellow, with a reddish tinge,
transversely striated.
_S. Haliotoideus._ The Haliotis-shaped Sigaretus.
Species thick, solid, depressed; spire flattish, aperture exposing the
whole of the interior.