DetailsPentremites pyriformis blastoid collected from Mississippian sediments in Sulphur, Indiana, 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 between 1 - 1.5 cm in diameter. Supplied in small plastic bags with an information label.