Phylum Mollusca, Class Cephalopoda

Cretaceous.  The cephalopods are considered to be the most highly advanced of the molluscs. All are marine, and the foot is modified to form a series of tentacles and a head. In some the shell is external, but in the most familiar cephalopods the shell is internal or absent.
Abstract/Description: Cretaceous. The cephalopods are considered to be the most highly advanced of the molluscs. All are marine, and the foot is modified to form a series of tentacles and a head. In some the shell is external, but in the most familiar cephalopods the shell is internal or absent.
Subject(s): Wisconsin, United States
environmental sciences