Tyrannosaurus rex, brain endocast Dimetrodon Discovered in 1923–27 during excavations

Discovered in 1923–27 during excavations at Zhoukoudian near Beijing (written "Peking" China

The evidence provided by a wide range of skeletal remains points toward considerable variation within the genus Proconsul

Juvenile Dimetrodon Skeleton

The wingspan ranges up to 7 feet 8 inches

Tyrannosaurus rex, brain endocast Dimetrodon Discovered in 1923–27 during excavationsThis is the endocranial skull cast of the brain cavity from an adult T rex. Cretaceous Age. For all it's size and strength, T. rex was relatively small brained. The last photo shows a brin case with labeled features. Late Cretaceous (70 m. y. a.) North America Shipping Included