"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 the top of the skull; in _Corythosaurus_ there is a thin high crest like the crown of a cassowary on top of the skull, and the muzzle is short and small giving a very peculiar aspect to the head. Complete skeletons of these two genera are exhibited in the Dinosaur Hall; the _Corythosaurus_ is worthy of careful study, as the skin of the body, hind limbs and tail, the ossified tendons, and even the impressions of the muscular tissues in parts of the body and tail, are more or less clearly indicated.
[Illustration: Fig. 34.--SKELETON OF SAUROLOPHUS, FROM UPPER CRETACIC OF ALBERTA. _After Brown_]
These Duck-billed Dinosaurs probably ranged all over North America and the northerly portions of the Old World during the later Cretacic. Fragmentary remains have been found in New Jersey and southward along the Atlantic coast. A partial skeleton was described many years ago by Leidy under the name of _Hadrosaurus_ and restored and mounted in the museum of the Philadelphia Academy of Sciences. _Telmatosaurus_ of the Gosau formation in Austria also belongs to this group, and fragmentary remains have been found in the upper Cretacic of Belgium, England and France.
[Footnote 16: Brown, Barnum. "The Trachodon Group." Amer. Mus. Jour. Vol. viii, pp. 51-56, plate and 3 text figs., 1908.]
[Footnote 17: Osborn, Henry Fairfield, "Dinosaur Mummy" Amer. Mus. Jour. Vol. xi, pp. 7-11, illustrated, Jan. 1911.]
[Footnote 18: There is some doubt whether this was really the condition during life. W.D.M.]