In the opening segment of "Follow the Bouncing Ball", Arthur and his friends are seen time traveling and visiting the Late Cretaceous Period, 65 million years ago. While doing so, the Brain leads the kids on a tour and points out an Apatosaurus. Apatosaurus is believed to have lived approximately 150 million years ago, in the Jurassic Period, which means that it would have been extinct for about 85 million years prior to the time period that the kids are visiting.