DetailsPentremites hambachi blastoid collected from the Mississippian Gasper Formation of Huntsville, Alabama, 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 cm in diameter. Supplied in small plastic bags with an information label.