Shell small, thin, sub-cylindrical, with sunken spire and about 3 visible whorls, constricted around the middle, and dilated at base. Surface longitudinally striated throughout, but not transversely sculptured. The aperture is somewhat longer than the shell, very narrow above and dilated and pyriform toward the base. Columella without folds. The soft parts have not been described. The animal in other species of this genus can retract completely into its shell. The head-shield is short, produced backwards in two narrow lateral tentacular processes. The short-ovate foot has no parapodial lobes. Operculum absent. Three subtriangular gizzard plates, corneus with two blunt tubercles.
dead shells are white.
common size :
about 4 mm.
Bogi and Khairallah (1987) proposed the synonym of P. fourierii with both Retusa dilatata Pallary, 1904 and Retusa dilatata var. minor Pallary, 1904. Nevertheless, Tringali and Oliverio (2001) after the examination of syntypes, concluded that both forms are closely related to the Mediterranean Retusa truncatula, from which P. fourierii can be distinguished by its larger size, more dilated lower part of the aperture, and by its definite sculpture covering the entire surface.
BIOLOGY / ECOLOGY
The retusids live in soft bottoms and feed upon foraminiferans or micro-molluscs.
in the Mediterranean this species has been dredged from sandy and muddy bottoms 40-70 m deep (van Aartsen et. al., 1989).