One of the two subphyla into which the phylum Echinodermata had been customarily divided. The Eleutherozoa are now best considered as comprising at least two distinct subphyla: (1) the Echinozoa, spherical-bodied forms with meridional symmetry; and (2) the Asterozoa, star-shaped forms with radially divergent axes of symmetry. The Echinozoa would seem to have arisen from ancestors similar to cystoids, whereas the Asterozoa seem to be derived from crinoidlike forms.