Orthoceras is a “Cephalopod” meaning head and foot, which protruded out of the same shell cavity. It was a prehistoric sea creature related to the modern squid, and octopus family. These creatures grew as much as 60 feet in length. Unlike their modern day cousins which have a translucent body, The bodies of the Orthocerida (the order that the animals belonged to) were orthoconic, long and straight. 

Orthoceras

Orthoceras