so note that there are also very large versions available.
Echinoderms (Phylum Echinodermata) are an exclusively marine invertebrate animal species displaying radial symmetry as adults.
Member Classes include Asteroidea (starfish), Echinoidea (sea urchins and sand dollars), Crinoidea (stone lillies and feather stars), Holothurians (sea cucumbers) and Ophiuroidea (brittle stars).
Their extinct ancestors constitute a much larger group and have left behind an extensive fossil record. [fossil pictures]
The images above come from a multi-volume series of monographs from the 1840s entitled: 'Monographies d'Échinodermes Vivans et Fossiles' (Monographs of living and fossilised echinoderms).
Wikipedia // Echinoid Directory // Tree of Life // The Echinoblog