DINOSAURS
Chapter 4:
THE CARNIVOROUS DINOSAURS, ALLOSAURUS, TYRANNOSAURUS,
ORNITHOLESTES, Etc.
Sub-Order
Theropoda.
The sharp teeth,
compressed and serrated like a palaeolithic spear point, and the powerful
sharp-pointed curved claws on the feet, prove the carnivorous habits of these
dinosaurs. The well-finished joints, dense texture of the hollow bones and
strongly marked muscle-scars indicate that they were active and powerful beasts
of prey. They range from small slender animals up to the gigantic
Tyrannosaurus equalling the modern elephant in bulk.
They were half lizard, half bird in proportions, combining the head, the short
neck and small fore limbs and long snaky tail of the lizard with the short,
compact body, long powerful hind limbs and three-toed feet of the bird. The skin
was probably either naked or covered with horny scales as in lizards and snakes;
at all events it was not armor-plated as in the crocodile.[4] They walked or ran
upon the hind legs; in many of them the fore limbs are quite unfitted for
support of the body and must have been used solely in fighting or tearing their
prey.
Fig. 10.—Hind Limb of Allosaurus, Dr. J.L. Wortman
standing to one side. Dr. Wortman is one of the most
notable and successful collectors of fossil
vertebrates and was in charge of the Museum's field
work in this department from 1891-1898.
The huge size of some of these Mesozoic beasts of
prey finds no parallel among their modern analogues. It
is only among marine animals that we find predaceous
types of such gigantic size. But among the carnivorous
dinosaurs we fail to find any indications of aquatic or
even amphibious habits. They might indeed wade in the
water, but they could hardly be at home in it, for they
were clearly not good swimmers. We must suppose that
they were dry land animals or at most swamp dwellers.
Dinosaur Footprints. The ancestors of the
Theropoda appear first in the Triassic period, already
of large size, but less completely bipedal than their
successors. Incomplete skeletons have been found in the
Triassic formations of Germany[5] but in this country
they are chiefly known from the famous fossil footprints
(or "bird-tracks" as they were at first thought to be),
found in the flagstone quarries at Turner's Falls on the
Connecticut River, in the vicinity of Boonton, New
Jersey, and elsewhere. These tracks are the footprints
of numerous kinds of dinosaurs, large and small, mostly
of the carnivorous group, which lived in that region in
the earlier part of the Age of Reptiles, and much has
been learned from them as to the habits of the animals
that made them. The tracks ascribed to carnivorous
dinosaurs run in series with narrow tread, short or long
steps, here and there a light impression of tail or
forefoot and occasionally the mark of the shank and
pelvis when the animal settled back and squatted down to
rest a moment. The modern crocodiles when they lift the
body off the ground, waddle forward with the short limbs
wide apart, and even the lizards which run on their hind
legs have a rather wide tread. But these dinosaurs ran
like birds, setting one foot nearly in front of the
other, so that the prints of right and left feet are
nearly in a straight line. This was on account of their
greater length of limb, which made it easy for them to
swing the foot directly underneath the body at each step
like mammals and birds, and thus maintain an even
balance, instead of wabbling from side to side as short
legged animals are compelled to do.
Of the animals that made these innumerable tracks the
actual remains found thus far in this country are
exceedingly scanty. Two or three incomplete skeletons of
small kinds are in the Yale Museum, of which
Anchisaurus is the best known.
Megalosaurus. Fragmentary remains of this huge
carnivorous dinosaur were found in England nearly a
century ago, and the descriptions by Dean Buckland and
Sir Richard Owen and the restorations due to the
imaginative chisel of Waterhouse Hawkins, have made it
familiar to most English readers. Unfortunately it was,
and still remains, very imperfectly known. It was very
closely related to the American Allosaurus and
unquestionably similar in appearance and habits.[6]
ALLOSAURUS.
The following extract is from the American Museum
Journal for January 1908.[7]
"Although smaller than its huge contemporary
Brontosaurus, this animal is of gigantic proportions
being 34 feet 2 inches in length, and 8 feet 3 inches
high."
After Osborn
Fig. 11.—Mounted
Skeleton of Allosaurus in the American Museum.
History of the Allosaurus Skeleton. "This rare
and finely preserved skeleton was collected by Mr. F.F.
Hubbell in October 1879, in the Como Bluffs near
Medicine Bow, Wyoming, the richest locality in America
for dinosaur skeletons, and is a part of the great
collection of fossil reptiles, amphibians and fishes
gathered together by the late Professor E.D. Cope, and
presented to the American Museum in 1899 by President
Jesup.
"Shortly after the Centennial Exposition (1876) it
had been planned that Professor Cope's collection of
fossils should form part of a great public museum in
Fairmount Park, Philadelphia, the city undertaking the
cost of preparing and exhibiting the specimens, an
arrangement similar to that existing between the
American Museum and the City of New York.[8]
"The plan, however, fell through, and the greater
part of this magnificent collection remained in storage
in the basement of Memorial Hall in Fairmount Park, for
the next twenty years. From time to time Professor Cope
removed parts of the collection to his private museum in
Pine Street, for purposes of study and scientific
description. He seems, however, to have had no idea of
the perfection and value of this specimen. In 1899 when
the collection was purchased from his executors by Mr.
Jesup, the writer went to Philadelphia under the
instructions of Professor Osborn, Curator of Fossil
Vertebrates, to superintend the packing and removal to
the American Museum. At that time the collection made by
Hubbell was still in Memorial Hall, and the boxes were
piled up just as they came in from the West, never
having been unpacked. Professor Cope's assistant, Mr.
Geismar, informed the writer that Hubbell's collection
was mostly fragmentary and not of any great value. Mr.
Hubbell's letters from the field unfortunately were not
preserved, but it is likely that they did not make clear
what a splendid find he had made, and as some of his
earlier collections had been fragmentary and of no great
interest, the rest were supposed to be of the same kind.
"When the Cope Collection was unpacked at the
American Museum, this lot of boxes, not thought likely
to be of much interest, was left until the last, and not
taken in hand until 1902 or 1903. But when this specimen
was laid out, it appeared that a treasure had come to
light. Although collected by the crude methods of early
days, it consisted of the greater part of the skeleton
of a single individual, with the bones in wonderfully
fine preservation, considering that they had been buried
for say eight million years. They were dense black, hard
and uncrushed, even better preserved and somewhat more
complete than the two fine skeletons of Allosaurus from
Bone-Cabin Quarry, the greatest treasures that this
famous quarry had supplied. The great carnivorous
dinosaurs are much rarer than the herbivorous kinds, and
these three skeletons are the most complete that have
ever been found. In all the years of energetic
exploration that the late Professor Marsh devoted to
searching for dinosaurs in the Jurassic and Cretaceous
formations of the West, he did not obtain any skeletons
of carnivorous kinds anywhere near as complete as these,
and their anatomy was in many respects unknown or
conjectural. By comparison of the three Allosaurus
skeletons with one another and with other specimens of
carnivorous dinosaurs of smaller size in this and other
museums, particularly in the National Museum and the
Kansas University Museum, we have been able to
reconstruct the missing parts of the Cope specimen with
very little possibility of serious error."
Evidence for Combining and Posing this Mount.
"An incomplete specimen of Brontosaurus, found by Doctor
Wortman and Professor W.C. Knight of the American Museum
Expedition of 1897, had furnished interesting data as to
the food and habits of Allosaurus, which were confirmed
by several other fragmentary specimens obtained later in
the Bone-Cabin Quarry. In this Brontosaurus skeleton
several of the bones, especially the spines of the tail
vertebrae, when found in the rock, looked as if they had
been scored and bitten off, as though by some
carnivorous animal which had either attacked the
Brontosaurus when alive, or had feasted upon the
carcass. When the Allosaurus jaw was compared with these
score marks, it was found to fit them exactly, the
spacing of the scratches being the same as the spacing
of the teeth. Moreover, on taking out the Brontosaurus
vertebrae from the quarry, a number of broken off teeth
of Allosaurus were found lying beside them. As no other
remains of Allosaurus or any other animal were
intermingled with the Brontosaurus skeleton, the most
obvious explanation was that these teeth were broken off
by an Allosaurus while devouring the Brontosaurus
carcass. Many of the bones of other herbivorous
dinosaurs found in the Bone-Cabin Quarry were similarly
scored and bitten off, and the teeth of Allosaurus were
also found close to them.
"With these data at hand the original idea was
conceived of combining these two skeletons, both from
the same formation and found within a few miles of each
other, to represent what must actually have happened to
them in the remote Jurassic period, and mount the
Allosaurus skeleton standing over the remains of a
Brontosaurus in the attitude of feeding upon its
carcass. Some modifications were made in the position to
suit the exigencies of an open mount, and to accommodate
the pose to the particular action; the head of the
animal was lifted a little, one hind foot planted upon
the carcass, while the other, resting upon the ground
bears most of the weight. The fore feet, used in these
animals only for fighting or for tearing their prey, not
for support, are given characteristic attitudes, and the
whole pose represents the Allosaurus devouring the
carcass and raising head and fore foot in a threatening
manner as though to drive away intruders. The balance of
the various parts was carefully studied and adjusted
under direction of the curator. The preparation and
mounting of the specimen were done by Mr. Adam Hermann,
head preparator, and his assistants, especially Messrs.
Falkenbach and Lang.
After Osborn
Fig.
12.—Restoration of Allosaurus by C.R. Knight.
"As now exhibited in the Dinosaur Hall, this group
gives to the imaginative observer a most vivid picture
of a characteristic scene in that bygone age, millions
of years ago, when reptiles were the lords of creation,
and 'Nature, red in tooth and claw' had lost none of her
primitive savagery, and the era of brute force and
ferocity showed little sign of the gradual amelioration
which was to come to pass in future ages through the
predominance of superior intelligence."
Appearance and Habits of Allosaurus. A study
of the mechanism of the Allosaurus skeleton shows us in
the first place that the animal is balanced on the hind
limbs, the long heavy tail making an adequate
counterpoise for the short compact body and head. The
hind limbs are nine feet in length when extended, about
equal to the length of the body and neck, and the bones
are massively proportioned. When the thigh bone is set
in its normal position, as indicated by the position of
the scars and processes for attachment of the principal
muscles (see under Brontosaurus for the method used to
determine this), the knee bends forward as in mammals
and birds, not outward as in most modern reptiles. The
articulations of the foot bones show that the animal
rested upon the ends of the metapodials, as birds and
many mammals do, not upon the sole of the foot like
crocodiles or lizards. The flat vertebral joints show
that the short compact body was not as flexible as the
longer body of crocodiles or lizards, in which the
articulations are of the ball and socket type showing
that in them this region was very flexible. The tail
also shows a limited flexibility. It 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.
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 keen vision of the bird, the
highly developed reasoning power of both, were absent in
the dinosaur as in the lizard or crocodile. We may
imagine the Allosaurus lying in wait, watching his prey
until its near approach stimulates him into a
semi-instinctive activity; then a sudden swift rush, a
fierce snap of the huge jaws and a savage attack with
teeth and claws until the victim is torn in pieces or
swallowed whole. But the stealthy, persistent tracking
of the cat or weasel tribe, the intelligent generalship
of the wolf pack, the well planned attack at the most
vulnerable point in the prey, characteristic of all the
predaceous mammals, would be quite impossible to the
dinosaur. By watching the habits of modern reptiles we
may gain a much better idea of his capacities and
limitations than if we judge only from the efficiency of
his teeth and claws, and forget the inferior
intelligence that animated these terrible weapons.
TYRANNOSAURUS.
The "Tyrant Saurian" as Professor Osborn has named
him, was the climax of evolution of the giant
flesh-eating dinosaurs. It reached a length of
forty-seven feet, and in bulk must have equalled the
mammoth or the mastodon or the largest living elephants.
The massive hind limbs, supporting the whole weight of
the body, exceeded the limbs of the great proboscideans
in bulk, and in a standing position the animal was
eighteen to twenty feet high, as against twelve for the
largest African elephants or the southern mammoth. The
head (see frontispiece) is 4 feet 3 inches long, 3 ft. 4
inches deep, and 2 ft. 9 inches wide; the long deep
powerful jaws set with teeth from 3 to 6 inches long and
an inch wide. To this powerful armament was added the
great sharp claws of the hind feet, and probably the
fore feet, curved like those of eagles, but six or eight
inches in length.
During ten years explorations in the Western
Cretaceous formations, Mr. Brown has secured for the
Museum three skeletons of this magnificent dinosaur,
incomplete, but finely preserved. The first, found in
1900, included the jaws, a large part of backbone and
ribs, and some limb bones. The second included most of
skull and jaws, backbone, ribs and pelvis and the hind
limbs and feet, but not tail. The third consisted of a
perfect skull and jaws, the backbone, ribs, pelvis and
nearly all of the tail, but no limbs. From these three
specimens it has been possible to reconstruct the entire
skeleton. The exact construction of the 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.
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.
Fig.
15.—Model of
Tyrannosaurus group for the Cretaceous Dinosaur
Hall.
"The fourth pose or study, for the proposed full
sized mount, is that of two reptiles of the same size
attracted to the same prey. One reptile is crouching
over its prey (which is represented by a portion of a
skeleton). The object of this depressed pose is to bring
the perfectly preserved skull and pelvis very near the
ground within easy reach of the visiting observer. The
second reptile is advancing, and attains very nearly the
full height of the animal. The general effect of this
group is the best that can be had and is very realistic,
particularly the crouching figure. A fifth study will
embody some further changes. The upright figure is not
well balanced and will be more effective with the feet
closer together, the legs straighter and the body more
erect. These reptiles have a series of strong abdominal
ribs not shown in the models. The fourth position places
the pelvis in an almost impossible position as will be
noted from the ischium and pubis.
"The lateral view of this fourth pose represents the
animals just prior to the convulsive single spring and
tooth grip which distinguishes the combat of reptiles
from that of all mammals, according to Mr. Ditmars.
"The rear view of the standing skeleton displays the
peculiarly avian structure of the iliac junction with
the sacral plate, characteristic of these very highly
specialized dinosaurs, also the marked reduction of the
upper end of the median metatarsal bone, which formerly
was believed to be peculiar to Ornithomimus."
This model of the group is on exhibition with the
mounted skeleton.
As compared with its predecessor Allosaurus,
the Tyrannosaurus is much more massively
proportioned throughout. The skull is more solid, the
jaws much deeper and more powerful, the fore limb much
smaller, the tail shorter, the hind limb straighter and
the foot bones more compacted so that the animal was
more strictly "digitigrade," approaching the ostriches
more closely in this particular.
Fig. 16.—Skeleton
of Tyrannosaurus in comparison with human skeleton.
This animal probably reached the maximum of size and
of development of teeth and claws of which its type of
animal mechanism was capable. Its bulk precluded
quickness and agility. It must have been designed to
attack and prey upon the ponderous and slow moving
Horned and Armored Dinosaurs with which its remains are
found, and whose massive cuirass and weapons of defense
are well matched with its teeth and claws. The momentum
of its huge body involved a seemingly slow and lumbering
action, an inertia of its movements, difficult to start
and difficult to shift or to stop. Such movements are
widely different from the agile swiftness which we
naturally associate with a beast of prey. But an animal
which exceeds an average elephant in bulk, no matter
what its habits, is compelled by the laws of mechanics
to the ponderous movements appropriate to its gigantic
size. These movements, directed and controlled by a
reptilian brain, must needs be largely automatic and
instinctive. We cannot doubt indeed that the Carnivorous
Dinosaurs developed, along with their elaborately
perfected mechanism for attack, an equally elaborate
series of instincts guiding their action to effective
purpose; and a complex series of automatic responses to
the stimulus afforded by the sight and action of their
prey might very well mimic intelligent pursuit and
attack, always with certain limits set by the inflexible
character of such automatic adjustments. But no animal
as large as Tyrannosaurus could leap or spring
upon another, and its slow stride quickening into a
swift resistless rush, might well end in unavoidable
impalement upon the great horns of Triceratops,
futile weapons against a small and active enemy, but
designed no doubt to meet just such attacks as these. A
true picture of these combats of titans of the ancient
world we cannot draw; perhaps we will never be able to
reconstruct it. But the above considerations may serve
to show how widely it would differ from the pictures
based upon any modern analogies.
One may well inquire why it is that no such gigantic
carnivora have evolved among the mammalian land animals.
The largest predaceous quadrupeds living today are the
lion and tiger. The bears although some of them are much
larger, are not generally carnivorous, except for the
polar bear, which is partly aquatic, preying chiefly
upon seals and fish. There are indeed carnivorous whales
of gigantic size, but no very large land carnivore.
There were, it is true, during the Tertiary and
Pleistocene, lions and other carnivores considerably
larger than the living species. But none of them
attained the size of their largest herbivorous
contemporaries, or even approached it. Among the
dinosaurs on the other hand we find that—setting aside
Brontosaurus and its allies as aquatic—the predaceous
kinds equalled or exceeded the largest of the
herbivorous sorts. The difference is striking, and it
does not seem likely that it is merely accidental.
The explanation lies probably in the fact that the
large herbivorous mammals are much more intelligent and
active, and would be able to use their weapons of
defense so as to defy the attacks of relatively slow
moving giant beasts of prey, as they do also the more
active but less powerful assaults of smaller ones. The
elephant or the rhinoceros is in fact practically immune
from the attacks of carnivora, and would still be so
were the carnivora to increase in size. The large modern
carnivora prey upon herbivores of medium or smaller
size, which they are active enough to surprise or run
down. Carnivora of much larger size would be too slow
and heavy in movements to catch small prey, while the
larger herbivores by intelligent use of their defensive
weapons could still fend them off successfully. In
consequence giant carnivores would find no field for
action in the Cenozoic world, and hence they have not
been evolved.
But the giant herbivorous dinosaurs, well armed or
well defended though they were, had not the intelligence
to use those weapons effectively under all
circumstances. Thus they might be successfully attacked,
at least sometimes, by the powerful although slow moving
Megalosaurians.
The suggestion has also been made that these giant
carnivores were carrion-eaters rather than truly
predaceous. The hypothesis can hardly be effectively
supported nor attacked. It is presented as a possible
alternate.
Albertosaurus. Closely allied to the
Tyrannosaurus but smaller, about equal in size to
Allosaurus, was the Albertosaurus of the
Edmonton formation in Canada. It is somewhat older than
the Tyrannosaur although still of the late Cretacic
period, and may have been ancestral to it. A fine series
of limbs and feet as also skull, tail, etc., are in the
Museum's collections. At or about this time carnivorous
dinosaurs of slightly smaller size are known to have
inhabited New Jersey; a fragmentary skeleton of one
secured by Professor Cope in 1869 was described as
Laelaps (=Dryptosaurus).[10]
Ornitholestes. In contrast with the
Allosaurus and Tyrannosaurus this skeleton
represents the smaller and more agile carnivorous
dinosaurs which preyed upon the lesser herbivorous
reptiles of the period. These little dinosaurs were
probably common during all the Age of Reptiles, much as
the smaller quadrupeds are today, but skulls or
skeletons are rarely found in the formations known to
us. The Anchisaurus, Podokesaurus and
other genera of the Triassic Period have left
innumerable tracks upon the sandy shales of the Newark
formation, but only two or three skeletons are known. A
cast of one of them is exhibited here. The original is
preserved in the Yale Museum. In the succeeding Jurassic
Period we have the Compsognathus, smallest of
known dinosaurs, and this Ornitholestes some six
feet long. A cast of the Compsognathus skeleton
is shown, the original found in the lithographic
limestone of Solenhofen is preserved in the Munich
Museum. The Ornitholestes is from the Bone-Cabin
Quarry in Wyoming. The forefoot with its long slender
digits is supposed to have been adapted for grasping an
active and elusive prey, and the name (Ornitho-lestes
= bird-robber) indicates that that prey may sometimes
have been the primitive birds which were its
contemporaries. In the Cretacic Period, there were also
small and medium sized carnivorous dinosaurs,
contemporary with the gigantic kinds; a complete
skeleton of Ornithomimus at the entrance to the
Dinosaur Hall finely illustrates this group. In
appearance most of these small dinosaurs must have
suggested long-legged bipedal lizards, running and
walking on their hind limbs, with the long tail
stretched out behind to balance the body. From what we
know of their tracks it seems that they walked or ran
with a narrow treadway, the footsteps almost in the
middle line of progress. They did not hop like perching
birds, nor did they waddle like most living reptiles.
Occasionally the tail or fore feet touched the ground as
they walked; and when they sat down, they rested on the
end of the pubic bones and on the tail. So much we can
infer from the footprint impressions. The general
appearance is shown in the restorations of
Ornitholestes, Compsognathus and
Anchisaurus by Charles Knight.
Fig.
17.—Skeleton of
Ornitholestes a small carnivorous dinosaur of
the Jurassic period. American Museum No. 619.
After Osborn
Fig. 18.—Restoration of Ornitholestes, by
C.R. Knight under direction of Professor Osborn.
Ornithomimus. The skeleton of this animal from
the Cretacic of Alberta was found by the Museum
expedition of 1914. It is exceptionally complete, and
has been mounted as a panel, in position as it lay in
the rock, and with considerable parts of the original
sandstone matrix still adherent. The long slender limbs,
long neck, small head and toothless jaws are all
singularly bird-like, and afford a striking contrast to
the Tyrannosaurus. At the time of writing, its
adaptation and relationships have not yet been
thoroughly investigated.
Fig. 19.—Mounted
Skeleton of Brontosaurus in the American Museum.
FOOTNOTES:
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