''Cryptoblastus'' is a genus of extinct

blastoid Blastoids (class Blastoidea) are an extinct type of stemmed echinoderm, often referred to as sea buds. They first appear, along with many other echinoderm classes, in the Ordovician period, and reached their greatest diversity in the Mississi ...

s, a primitive group of

echinoderm An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the s ...

s related to the modern

sea lilies Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which ar ...

. Fossils are found in sedimentary rocks laid down in the

Early Carboniferous Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early ...

period some 360 to 320 million years ago. ''Cryptoblastus''. (2011). In Encyclopædia Britannica. Retrieved from http://www.britannica.com/EBchecked/topic/145001/Cryptoblastus

References

Blastozoa genera Paleozoic life of Alberta Carboniferous echinoderms {{paleo-echinoderm-stub