The skeleton of an elasmosaurus, a dinosaur in the order of plesiosaurs.

Elasmosaurus Skeleton

The skeleton of an elasmosaurus, a dinosaur in the order of plesiosaurs.

The skeleton of Ichthyosaurus.

Ichthyosaurus

The skeleton of Ichthyosaurus.

The now extinct pachyderm, the mammoth.

Mammoth

The now extinct pachyderm, the mammoth.

The mammoth.

Mammoth

The mammoth.

The passenger pigeon was very abundant in North America but eventually became extinct because of hunting.

Passenger Pigeon

The passenger pigeon was very abundant in North America but eventually became extinct because of hunting.

Scaphites equalis is a species of extinct cephalopods that thrived during the Cretaceous period.

Scaphites

Scaphites equalis is a species of extinct cephalopods that thrived during the Cretaceous period.

The dorsal view of Eurypterus remipes, an extinct sea scorpion from the Silurian period.

Dorsal View of Sea Scorpion

The dorsal view of Eurypterus remipes, an extinct sea scorpion from the Silurian period.