DetailsPentremites sp. blastoid collected from Pennsylvanian sediments in Indiana or Oklahoma, USA. Pentremites belong to the class Blastoidea and they are a type of echinoderm. They resemble their distant relatives, the crinoids, being attached to the sea floor by a stalk, trapping food with tentacle like appendages. These specimens measure approximately 1.5 cm - 2 cm in diameter. Supplied in small plastic bags with an information label.