Platycrinites saffordi, Catillocrinus sp., Macrocrinus sp.
Mississippian
Crawfordsville, Indiana
Distinguished by the presence of two roots (circular bases, each with five arms), a large and impressive crinoid plaque also displays several sections of stems and five crowns (one from a juvenile.) Also known as Sea Lillies, crinoids belong to the invertebrate phylum Echinodermata, and have their own class, Crinoidea. Some species attach to the ocean floor by a root; a stem attaches the root to the crown; the crown has arms, and the arms have feather-like pinnules. These crinoids can move by manipulating the arms of the root. Prehistoric crinoid forests swayed back and forth in the ocean currents. Crinoids are filter feeders, grabbing microscopic particles on which to feed. Distant relatives include the starfish, brittle star and sea urchins. The present seafloor plaque displays three fascinating species of crinoids.
Matrix measures 20 x 15 x 3 1/2in