ns of limbs and feet
to enable them to support its weight. They were evidently herbivorous
and some of them of gigantic size. Smaller kinds with less massive
armor have been found in Europe but the largest and most extraordinary
members of this strange race are from North America.

STEGOSAURUS.

This extraordinary reptile equalled the Allosaurus in size, and bore
along the crest of the back a double row of enormous bony plates
projecting upward and somewhat outward alternately to one side and the
other. The largest of these plates situated just back of the pelvis
were over two feet high, two and a half long, thinning out from a base
four inches thick. The tail was armed with four or more stout spines
two feet long and five or six inches thick at the base. In the neck
region and probably elsewhere the skin had numerous small bony nodules
and some larger ones imbedded in its substance or protecting its
surface. The head was absurdly small for so huge an animal, and the
stiff thick tail projected backward but was not long enough to reach
the ground. The hind limbs are very long and straight, the fore limbs
relatively short, and the short high arched back and extremely deep
and compressed body served to exaggerate the height and prominence of
the great plates. The surface of these plates, covered with a network
of blood-vessels, shows that they bore a covering of thick horny skin
during life, which probably projected as a ridge beyond their edges
and still further increased their size. The spines of the tail, also,
were probably cased in horn.

This extraordinary animal was a contemporary of the Brontosaurus and
Allosaurus, and its discovery was one of the great achievements of the
late Professor Marsh. The skeletons which he described are mounted in
the Yale and National Museums. Another skeleton was found in the
famous Bone-Cabin Quarry, near Medicine Bow, Wyoming, by the American
Museum Expedition of 1901. This skeleton, at present withdrawn from
lack of space, will be mounted in the Jurassic Dinosaur Hall in the
new wing now under construction.

[Illustration: Fig. 35.--Skull and lower jaw of Armored Dinosaur
_Ankylosaurus_, from Upper Cretacic (Edmonton formation) of
Alberta. Left side view. _After Brown_]

ANKYLOSAURUS.

Related to _Stegosaurus_, equally huge, but very different in
proportions and character of its armor was the Ankylosaurus of the
late Cretacic. This animal, a contemporary of the Tyr