CHAPTER VII.
THE BEAKED DINOSAURS (Continued).
B.THE DUCK BILLED DINOSAURS,--TRACHODON, SAUROLOPHUS, ETC.
_Sub-Order Ornithopoda; Family Trachodontidae._ These animals of the Upper Cretaceous are probably descended from the Iguanodonts of an older period.

But the long ages that intervened, some millions of years, have brought about various changes in the race, not so much in general proportions as in altering the form and relations of various bones of skull and skeleton and perfecting their adaptation to a somewhat different habit of life, so that they must be regarded as descendants perhaps, but certainly rather distant relatives, of the older group.
We know more about the Trachodonts than any other dinosaurs.

For not only are the skeletons more frequently found articulated, but parts of the skin are not uncommonly preserved with them, and in one specimen at least, so much of the skin is preserved that it may fairly be called a "dinosaur mummy." This specimen of _Trachodon_ is in the American Museum, and beside it are two fine mounted skeletons of the largest size.

There is also on exhibition a panel mount of a nearly related genus, _Saurolophus_ the skeleton lying as it was found in the rock, and a fine skeleton of a third genus _Corythosaurus_ with the skin partly preserved on both sides of the crushed and flattened body stands beside it.

In the _Tyrannosaurus_ group when completed will appear a fourth skeleton of the _Trachodon_.