The Orthoceras was an ancient cephalopod (like the octopus, squid, etc.) that lived 370 million years ago. It was a hunter of the Paleozoic Seas. The siphuncle is the tube that you will notice runs the length of these ancient animals, which they used to propel themselves and also for buoyancy. These 2-3" polished orthoceras fossils can be drilled and used as pendants, necklaces, or as a decoration. They are great for fossil collectors. No two are identical since they are objects from nature.