Samuel T. Philander, Professor Porter's academic rival, who often takes credit for the Professor's findings and research, visits Africa believing that the Professor has found something there. The Professor does discover something, but only after Philander arrives - Tarzan shows Jane and him Pellucidar, a place beneath Africa where dinosaurs still live. Philander takes a camera - not knowing that a baby baboon had already used up all the film taking pictures of itself - but the Professor has none, until he tries to steal a Tyrannosaurus rex egg, which hatches. This arouses the fury of the mother, who chases them until Porter returns the egg and they escape. Meanwhile, Philander returns to London unveiling proof of dinosaurs - only to discover the baboon's pictures.