The polyplacophora, commonly known as the chitons, are sluggish crawlers on the sea bottom. A chiton averages in size from 1 to 3 inches long and it's width amounts to to about a third to a fourth of it's length.

The body is bilaterally symmetrical, with is characteristic subdivision of the calcareous shell into eight articulating plates with joints between them running transverse to the axis of the body. The animal conforms to irregular hard surfaces and, if torn off by heavy seas, will curl up, bending at each joint between the shell pieces, to protect the underside of the body. Colouration of the upper part of the shells is quite variable, even between individuals of the same species. Black, brown, white and various tints of red and green form the usual colour range, some species being quite strikingly maculated or banded.


They live on or under rocks, in the interstices of coral, in coral holes, and in seaweed holdfasts. They are found mostly in the littoral zone (shore dwelling) but may be present at all depths. They typically inhabit rocky, surf-beaten shores.