Reconstruction of the crinoid, Echmatocrinus brachiatus, from the Middle Cambrian Burgess Shale of British Columbia. Known from only five specimens, this first-known crinoid is composed of polygonal calcite plates and eight uniserial arms with exceptionally well-preserved tube feet. Filtering food particles from the seawater, this sessile echinoderm affixed itself to hard surfaces by means of a small, round holdfast. Specimens are up to 8 cm. in height.