the world > animals > invertebrates > subkingdom Metazoa > grade Triploblastica or Coelomata > class Cephalopoda > [noun] > order Tetrabranchiata > family Orthoceratidae > genus Orthoceras > member of > fossil shell of (1)
orthoceratite1734
A fossil shell of a nautiloid cephalod mollusc of the Palaeozoic or early Mesozoic eras, having a long, straight (or nearly straight) chambered…