Class Scaphopoda
The scaphopods or tusk shells are strictly marine mollusks and usually inhabit the deepest regions of the oceans. These mollusks are elongated and symmetrical, with a long, conical foot. Receiving their name from the tusk-like shape of their shell. The head has no eyes or tentacles but the mouth does have a radula.
The shells themselves are tubular and are open at both ends. At the wide end there is a round or oval opening called the aperture while the smaller opening, the apex, is either smooth or has one or more slits or notches.
The mollusk's tentacles, foot and mouth stick out of the aperture and into the sand or mud where it will forage for food. The smaller en of the shell protrudes from the sand and inhales and exhales water via the siphons, which protrude from the apex.