fore feet is the only doubtful part. The
fore-limb is very small relatively to the huge size of the animal, but
probably was constructed much as in the _Allosaurus_ with two or three
large curved claws, the inner claw opposing the others.

[Illustration: Fig. 14.--Quarry from which the _Tyrannosaurus_
skeleton was taken. American Museum camp in foreground.]

The missing parts of the two best skeletons have been restored, and
with the help of two small models of the skeleton, a group has been
made ready for mounting as the central piece of the proposed
Cretaceous Dinosaur Hall. One of the skeletons is temporarily placed
in the centre of the Quaternary Hall, space for it in the present
Dinosaur Hall being lacking. Following is Professor Osborn's
description of the preparation of this group:[9]

"The mounting of these two skeletons presents mechanical problems of
very great difficulty. The size and weight of the various parts are
enormous. The height of the head in the standing position reaches from
18 to 20 feet above the ground; the knee joint alone reaches 6 feet
above the ground. All the bones are massive; the pelvis, femur and
skull are extremely heavy. Experience with _Brontosaurus_ and with
other large dinosaurs proves that it is impossible to design a
metallic frame in the right pose in advance of assembling the parts.
Even a scale restoration model of the animal as a whole does not
obviate the difficulty.

"Accordingly in preparing to mount _Tyrannosaurus_ for exhibition a
new method has been adopted, namely, to _prepare a scale model of
every bone in the skeleton_ and mount this small skeleton with
flexible joints and parts so that all studies and experiments as to
pose can be made with the models.

"This difficult and delicate undertaking was entrusted to Mr. Erwin
Christman of the artistic staff of the Department of Vertebrate
Palaeontology of the Museum, who has prepared two very exact models to
a one-sixth scale, representing our two skeletons of _Tyrannosaurus
rex_, which fortunately are of exactly the same size. A series of
three experiments by Mr. Christman on the pose of _Tyrannosaurus_,
under the direction of the author and Curator Matthew, were not
satisfactory. The advice of Mr. Raymond L. Ditmars, Curator of
Reptiles in the New York Zoological Park, was sought and we thus
obtained the fourth pose, which is shown in the photographs published
herewith.

[Illustration: Fig. 15.--Model of _T