The heteropods are transparent planktonic animals, whose systematic position has undergone considerable reappraisal since the last century. It was Lamarck who, in 1812, created the order Heteropoda, which he placed between the Cephalopoda and the fishes, and brought together the genera Carinaria, Firola and Phyllirhoë. Later, Cuvier (1829) added to these the genus Atlanta. [NOT CONTROLLED OCR]