_Monoclonius_, _Ceratops_, _Torosaurus_ and _Anchiceratops_ are also of this group.

All from the Cretacic period.
_Classification of Dinosaurs._ It is probable that the Dinosaurs are not really a natural group or order of reptiles, although they have been generally so considered.

The Carnivorous and Amphibious Dinosaurs in spite of their diverse appearance and habits, are rather nearly related, while the Beaked Dinosaurs form a group apart, and may be descendants of a different group of primitive reptiles.

These relations are most clearly seen in the construction of the pelvis (see fig.

9).