Endorioceras
Endorioceras is an extinct genus of actively mobile carnivorous cephalopod of the family "Baltoceratidae" that lived in what would be North America during the Ordovician from 490–479 mya, existing for approximately . Taxonomy. "Endorioceras" was named by Flower (1964). It is not extant. Its type is "Endorioceras rarum". It was assigned to "Baltoceratidae" by Flower (1964); and to "Ellesmerocerida" by Sepkoski (2002). Morphology. The shell is usually long, and may be straight ("orthoconic") or gently curved. In life, these animals may have been similar to the modern squid, except for the long shell.