BCC124711 Blastoidea, plate from Artforms of Nature, c.1899-1904 (colour engraving) by Haeckel, Ernst (1834-1919); Calmann & King, London, UK; (add.info.: Blastoids (Class Blastoidea) are an extinct type of stemmed echinoderm; They originated in the Ordovician period and reached their greatest diversity in the Mississippian subperiod of the Carboniferous period. Blastoids persisted until their extinction at the end of Permian, about 250 million years ago. Blastoids were high-level, stalked suspension feeders (feeding mainly on planktonic organisms) that inhabited clear-to-silty, moderately-agitated ocean waters from shelf to basin.); German, out of copyright.