Aplacophora is a class of mollusks comprised of about 320 species. They were considered echinoderms until around 1987 when they were moved to Mollusca. Species ingest sediment while inhabiting burrows. A shell is lacking but the epidermis secretes a cuticle in which are embedded scales (seen above) that point posteriorly. The posterior end (right) contains the ctnedia (gills, and can be seen in the photo as the fluffy material at end) and the anus. The mouth located at the anterior (left) can also been seen (flat region on right side of anterior end). The internal structures anterior are the gut and posterior are a combination of the gut and gonad. This individual (Subclass Chaetoderma) is a about 3mm long.