Caption:
An extinct seasnake-like Mosasaur in the Niobrara sea, North America, late Cretaceous. A pterosaur, Pteranodon, at left, and sea turtle at right. Mosasaurs were probably giant sea monitor lizards of their time. Illustration from Wilhelm Bolsches Das Leben der Urwelt, Prehistoric Life, Georg Dollheimer, Leipzig, 1932.