annosaurus and
duck-billed dinosaurs was more effectively though less grotesquely
armored than its more ancient relative. The body is covered with
massive bony plates set close together and lying flat over the surface
from head to tip of tail. While the stegosaur's body was narrow and
compressed, in this animal it is exceptionally broad and the wide
spreading ribs are coossified with the vertebrae, making a very solid
support for the transverse rows of armor plates. The head is broad
triangular, flat topped and solidly armored, the plates consolidated
with the surface of the skull and overhanging sides and front, the
nostrils and eyes overhung by plates and bosses of bone; and the tail
ended in a blunt heavy club of massive plates consolidated to each
other and to the tip of the tail vertebrae. The legs were short,
massive and straight, ending probably in elephant-like feet. The
animal has well been called "the most ponderous animated citadel the
world has ever seen" and we may suppose that when it tucked in its
legs and settled down on the surface it would be proof even against
the attacks of the terrible Tyrannosaur.

[Illustration: Fig. 36.--_Ankylosaurus_, top view of skull in fig.
35. _After Brown_]

This marvellous animal was made known to science by the discoveries of
the Museum parties in Montana and Alberta under Barnum Brown.
Fragmentary remains of smaller relatives had been discovered by
earlier explorers but nothing that gave any adequate notion of its
character or gigantic size. From a partial skeleton discovered in the
Hell Creek beds of Montana, and others in the Edmonton and Belly River
formations of the Red Deer River, Alberta, it has been possible to
reconstruct the entire skeleton of the animal, save for the feet, and
to locate and arrange most of the armor plates exactly. A skeleton
mount from these specimens will shortly be constructed for the
Cretaceous Dinosaur Hall.

_Scelidosaurus, Polacanthus, etc._ Various armored dinosaurs, of
smaller size and less heavily plated, have been described from the
Jurassic, Comanchic and Cretacic formations of Europe. The best known
are _Scelidosaurus_ of the Lower Jurassic of England, and
_Polacanthus_ of the Comanchic (Wealden). _Stegopelta_ of the
Cretaceous of Wyoming is more nearly related to _Ankylosaurus_.

CHAPTER IX.

THE BEAKED DINOSAURS (Concluded.)

D. THE HORNED DINOSAURS, TRICERATOPS, ETC.

_Sub-Order Ceratopsia._

In 1887 Pro