These clams like their more famous Pacific relative P. generosa have an enlarged siphon that can extend to great lengths or contract to just barely poke out of the shell.

[1] They are generally smaller in comparison to the Pacific species though still constitute a sizable mollusc as they cannot fully retract their siphon.

[3] This species is known to range along the Atlantic Coast as far north as Chesapeake Bay and around the Florida Peninsula into the Northern Gulf of Mexico.

[3] The species is so poorly documented that it is unknown how far south along the Gulf Coast it ranges, though unconfirmed sightings from the Northern Yucatán Peninsula have been reported.

[4] The clams live in muddy soil and sometimes sand, usually buried deep down with only the tip of the siphon poking out from the substrate.