Members of the group were able to expand and contract their bodies, and some have speculated that they may have largely fed at night.

Most likely the extending and contracting played a role in gas exchange and nutrition intake as it generated a water current.

The rarity of fossils and general poor preservation of them has made it hard to determine any kind of phylogeny for them, though three genera (Helicoplacus, Polyplacus and Waucobella) are currently recognized.

[5] Also due to this, it is difficult to establish a conclusive taxonomic classification of the Helicoplacoidea.

This fossil measured 3.3 cm, and comes from the Cambrian formation of Poleta, California.