This picture shows the skull of a dinosaur called Centrosaurus. Centrosaurus was a bulky dinosaur from the late Cretaceous Period (around 76 million years ago). Photo taken in Victoria Museum, Melbourne, Australia.
The two rows of pterygoid teeth on the hard palate are visible at the back of the mosasaur's mouth. These were another adaptation that allowed the mosasaur to catch and swallow struggling, slippery prey in the middle of the ocean. not an easy feat