could not be curled or thrown over the back, but
projected out behind the animal, swinging from side to side or up and
down as much as was needed for balance. The curvature of the ribs
shows that the body was narrow and deep, unlike the broad flattened
body of the crocodile or the less flattened but still broad body of
the lizard. The loose hung jaw, articulated far back, shows by the set
of its muscles that it was capable of an enormous gape; while in the
skull there is evidence of a limited movement of the upper jaw on the
cranial portion, intended probably to assist in the swallowing of
large objects, like the double jointed jaw of a snake.

As to the nature of the skin we have no exact knowledge. We may be
sure that it had no bony armor like the crocodile, for remains of any
such armor could not fail to be preserved with the skeletons, as it
always is in fossil crocodiles or turtles. Perhaps it was scaly like
the skin of lizards and snakes, for the horny scales of the body are
not preserved in fossil skeletons of these reptiles. But if so we
might expect from the analogy of the lizard that the scales of the
head would be ossified and preserved in the fossil; and there is
nothing of this kind in the Carnivorous Dinosaurs. We can exclude
feathers from consideration, for these dinosaurs have no affinities to
birds, and there is no evidence for feathers in any dinosaur. Probably
the best evidence is that of the Trachodon or duck-billed dinosaur
although this animal was but distantly related to the Allosaurus. In
Trachodon (see p. 94), we know that the skin bore neither feathers nor
overlapping scales but had a curiously patterned mosaic of tiny
polygonal plates and was thin and quite flexible. Some such type of
skin as this, in default of better evidence, we may ascribe to the
Allosaurus.

[Illustration: Fig. 13.--View in the Hell Creek badlands in
central Montana, where the Tyrannosaurus skeleton was found.]

As to its probable habits, it is safe to infer (see p. 33), that it
was predaceous, active and powerful, and adapted to terrestrial life.
Its methods of attack and combat must have been more like those of
modern reptiles than the more intelligent methods of the mammalian
carnivore. The brain cast of Allosaurus indicates a brain of similar
type and somewhat inferior grade to that of the modern crocodile or
lizard, and far below the bird or mammal in intelligence. The keen
sense of smell of the mammal, the k