27 .-- Teeth of the duck-billed dinosaur _Trachodon_.

The dental magazine has been removed from the lower jaw and is seen to consist of several close-set rows of numerous small pencil-like teeth which are pushed up from beneath as they wear off at the grinding surface.] _Camptosaurus._ The American counterpart of the Iguanodons of Europe was the _Camptosaurus_, nearly related and generally similar in proportions but including mostly smaller species, and lacking some of the peculiar features of the Old World genus.

In the National Museum at Washington, are mounted two skeletons of _Camptosaurus_, a large and a small species, and in the American Museum a skeleton of a small species.

It suggests a large kangaroo in size and proportions, but the three-toed feet, with hoof-like claws, the reptilian skull, loosely put together, with lizard-like cheek teeth and turtle beak indicate a near relative of the great _Iguanodon_.
_Thescelosaurus._ The Iguanodont family survived until the close of the Age of Reptiles, with no great change in proportions or characters.

Its latest member is _Thescelosaurus_, a contemporary of _Triceratops_.