Douvilliceras Ammonite (No.21)

This shell is involute and compressed in profile. Strong, simple ribs pass over the rounded venter, and are each divided into numerous, even-sized tubercles, which would originally have carried long spines.

This genus was certainly a poor swimmer - the broad profile of the whorl, the shape of the shell offered considerable resistance to the water. Douvilleiceras may well have spent much time scavenging or hunting on the sea bed.