cystoids

Another Silurian resident of the Chicago region were cystoids.

Some new cystoids and crinoids appeared.

Cystoids of this age in Wisconsin were preserved in Racine County.

Superficially, the cystoids resembled crinoids, but they had an ovoid, rather than cup-shaped, body.

Ordovician cystoids were preserved in Smith County.

Blastozoa: the cystoids, an extinct group.

The most distinctive feature of cystoids was the presence of a number of pores in the rigid skeleton encasing the body.

Late Cambrian life in Minnesota included brachiopods, cystoids, graptolites, pteropods, a variety of trilobites, and worms.

Its end-Ordovician limestones contain a benthic fauna (brachiopods, bryozoans, cystoids) as well as conodonts.

Possible Silurian or Devonian life from Vermont included brachiopods, cephalopods, crinoids, cystoids, corals, and a possible trilobite.

Cystoids (class Cystoidea) are even odder animals: often rather irregular bags of calcite plates, or if composed of a few plates these may carry powerful ribbing.

About 340 million years ago Wisconsin was home to brachiopods, bryozoans, cephalopods, corals, crinoids, cystoids, gastropods, pelecypods, sponges, stomatoporoids, and trilobites.

The Cystoidea or cystoids, are extinct echinoderms that lived attached to the sea floor by stalks, and are distinguished from other echinoderms by triangular pore openings.

There are two competing hypotheses pertaining to the origin of the group: the traditional viewpoint holds that crinoids evolved from within the blastozoans (the eocrinoids and their derived descendants the cystoids), whereas the most popular alternative suggests that the crinoids split early from among the edrioasteroids.