The shells of this genus are generally small; found in the seas of hot
countries attached to madrepore and other marine substances.
Shell sessile, thin, Patella-shaped; aperture oval, rather large, closed
by a large sub-pyramidal bivalve operculum; a considerable calcareous
support, funnel-shaped, penetrating the bodies to which the animal is
attached.
Creusia stromia.
C. spinulosa.
C. verruca.
_C. spinulosa._ The spiny Creusia.
Very depressed, striated, sometimes with marks of division into four
pieces; operculum bivalve.
_C. verruca._ The warted Creusia. Pl. 4, fig. 2.
Whitish, slightly depressed, with interwoven obliquely striated valves;
the margin at the base irregularly serrated.