![](https://static.wixstatic.com/media/f867c2_a25aa693c87440f884308a0176828cf7~mv2.jpg/v1/fill/w_147,h_96,al_c,q_80,usm_0.66_1.00_0.01,blur_2,enc_auto/f867c2_a25aa693c87440f884308a0176828cf7~mv2.jpg)
In a pen shell, that is! Museum friend and collaborator Amy Tripp from Marco Island took this great photo of a pinnotherid crab (arrow) inside a pen shell (probably a Stiff Pen Shell, Atrina rigida). Pinnotherids are tiny, soft-bodied crabs that live inside the mantle and gills of some bivalve mollusks (and the occasional large gastropod such as a true conch (family Strombidae) or abalone (Haliotis species). Pinnotherid crabs are commensals, i.e., they take advantage of their hosts' meals or leftovers for their own feeding.