A Calymene trilobite
Calymene is an extinct genus of trilobites that lived from the Ordovician to Devonian periods, 485 to 407 million years ago. It usually had 12 "ribs" on it's body.
Dinopedia
A Calymene trilobite
Calymene is an extinct genus of trilobites that lived from the Ordovician to Devonian periods, 485 to 407 million years ago. It usually had 12 "ribs" on it's body.