Cephalopod shells may be coiled, slightly curved, or straight, and all are characterized by internal chambers. The cephalopod body, which included a head with eyes, mouth and tentacles, occupied the final and largest chamber.
All modern cephalopods are carnivores that capture and eat other animals.
All cephalopods are swimmers, but some, such as the octopus, spend most of their time on the seafloor. A t least 33 species of cephalopods lived as dwellers in the Silurian reefs of Wisconsin. Although the cephalopods in the diorama are shown as active swimmers, the larger forms may have spent most of their time lying on the reef surface.