Prehistoric marine animals. Artwork showing various extinct and living sea animals, plus a human diver, drawn to scale. Top row (left to right): Leedsichthys (27 metres), Styxosaurus (12 metres), Megalodon (20 metres). Second row: Dunkleosteus (10 metres), Shonisaurus (21 metres), Kronosaurus (10 metres), Liopleurodon (10 metres), Tylosaurus (15 metres). Bottom row: Xiphactinus (5 metres), Archelon (4 metres), human diver (1.8 metres) and blue whale (30 metres).