Fossil crinoid (Pterocoma). This now extinct genus of crinoids is found in late Jurassic and early Cretaceous deposits in Europe and North America. Crinoids, popularly known as sea-lilies, belong to a phylum known as Echinodermata. They have lived, in different forms, throughout the geological record from Palaeozoic times up to this day. Actual height of specimen is 210 mm.