Gulf of Mexico, Caribbean to Mediterranean. Deposit feeder, from circalittoral (mud, coralligen, uncommon) down to bathyal muds (rare). The species has the largest size in the western part of its range. – Above and below: 140m deep, on muddy bottom, off Ras ir-Raħeb, western coast of Malta. 6mm.

The species may be distinguished from Ennucula tenuis by its « usually smaller size, thinner texture, having a rounder and less oblique outline, and being more uniformly convex; the posterior side is more abruptly angular; the beaks are more gibbous, and straight instead of inclining to one side; the hinge-line is broader, and teeth fewer; and the cartilage and pit are shorter and smaller, and not placed so obliquely as in N. tenuis. » – J. G. Jeffreys: “On the Mollusca procured during the ‘Lightning’ and ‘Porcupine’ Expeditions, 1868-1870 (Part II)”, Proceedings of the Zoological Society of London, year 1879 part III, p.581-582. In fact, the beaks are inclining to one side: the anterior one (they are prosogyrate).