Description
These primitive members of the Phylum Cephalopoda are the ancestral cousin of the octopus or squid. The word orthoceras means “straight horn” and refers to its shape. All orthoceras have chambers separated by walls called septa. They also have a tube running down the center of the fossil called a siphuncle. It is believed this tube was used to carry gas into the chambers to control the buoyancy of the shell.
Orthoceras Fossil, Morocco. 400 million years old
Measures approx. 1.5-2.5 inches in length