(Woods S., 1839)
Description (shell):
The 7 mm internal shell (covered by the mantle) is oval to round in shape, fragile, translucent white; the aperture is very wide, and approximately as long as the spire. Minute sculpture is present consisting of spiral rows of oval dots, linked together in a chain-like manner.
Animal:
The overall length of the body may reach 16 mm, whitish and oval in shape (P. quadrata-animal).
Habitat:
This is an uncommon species, occurring sporadically in sublittoral sand. Very little is known of its ecology. The maximal depth recorded is 2150 m.
Distribution:
Distributed from Greenland, Iceland, White Sea, and NW Europe from Norway to the Mediterranean Sea, Azores and St Helena. It is also reported from the New England coast of north America (Distr. P. quadrata).