rom the
back and a lighter appearance when seen from the front.

[Illustration: Fig. 31.--The Dinosaur Mummy. Detail of skin of
under side of body. _After Osborn_]

[Illustration: Fig. 32.--Skin impression from the tail of a
_Trachodon_. The impressions appear to have been left by horny
scutes or scales, not overlapping like the scales on the body of
most modern reptiles, but more like the scutes on the head of a
lizard.]

[Illustration: Fig. 33.--Skull of Gila Monster (_Heloderma_), for
comparison of surface with skin impressions of _Trachodon_.
Enlarged to 4/3.]

"The thin character of the epidermis as revealed by this specimen
favors also the theory that these animals spent a large part of their
time in the water, which theory is strengthened by the fact that the
diminutive fore limb terminates not in claws or hoofs, but in a broad
extension of the skin, reaching beyond the fingers and forming a kind
of paddle.[18] The marginal web which connects all the fingers with
each other, together with the fact that the lower side of the fore
limb is as delicate in its epidermal structure as the upper,
certainly tends to support the theory of the swimming rather than the
walking or terrestrial function of this fore paddle as indicated in
the accompanying preliminary restoration that was made by Charles R.
Knight working under the writer's direction. One is drawn in the
conventional bipedal or standing posture while the other is in a
quadrupedal pose or walking position, sustaining or balancing the fore
part of the body on a muddy surface with its fore feet. In the distant
water a large number of animals are disporting themselves.

"The designation of these animals as the 'duck-billed' dinosaurs in
reference to the broadening of the beak, has long been considered in
connection with the theory of aquatic habitat. The conversion of the
fore limb into a sort of paddle, as evidenced by the Sternberg
specimen, strengthens this theory.

"This truly wonderful specimen, therefore, nearly doubles our previous
insight into the habits and life of a very remarkable group of
reptiles."

_Saurolophus, Corythosaurus._ In the latest Cretaceous formation, the
Lance or Triceratops beds, all the duck-billed dinosaurs are much
alike, and are referred to the single genus _Trachodon_. In somewhat
older formations of the Cretacic period there were several different
kinds. _Saurolophus_ has a high bony spine rising from t