The Minor Jacknife (Ensis megistus Pilsbry and McGinty, 1943) has a very delicate, elongate shell with an unusual coloration that includes purplish vertical bars internally. It is a burrower, living in fine sand and mud. Minor Jacknives inhabit and can move up and down vertical or oblique, cylindrical burrows. A Minor Jacknife can burrow rapidly by using its foot as a piston inside their dwelling. In some extreme cases, individuals are known to leap out of burrows to evade predators.
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The Minor Jacknife, Ensis megistus, internal (top) and external (bottom) views of the shell valves. Photo by José H. Leal.