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.
[Illustration: 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."
[Illustration: Fig. 11.--MOUNTED SKELETON OF ALLOSAURUS IN THE
AMERICAN MUSEUM. _After Osborn_]
_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.
[Illustration: Fig. 12.--Restoration of Allosaurus by C.R. Knight.
_After Osborn_]
"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.
[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 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.
[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 _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.
[Illustration: 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.
[Illustration: Fig. 17.--Skeleton of _Ornitholestes_ a small
carnivorous dinosaur of the Jurassic period. American Museum No.
619.]
[Illustration: Fig. 18.--Restoration of _Ornitholestes_, by C.R.
Knight under direction of Professor Osborn. _After 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.
[Illustration: Fig. 19.--MOUNTED SKELETON OF BRONTOSAURUS IN THE
AMERICAN MUSEUM.]
FOOTNOTES:
[Footnote 4: This is still doubtful in _Tyrannosaurus_. A number of
very curious plates were found with one specimen in a quarry. B.
Brown, 1913.]
[Footnote 5: Quite recently a series of more or less complete
skeletons have been secured from the upper Triassic (Keuper) near
Halberstadt in Germany. They are not true Megalosaurians, but
primitive types (Pachypodosauria) ancestral to both these and the
Sauropoda. Probably many of the Connecticut footprints were made by
animals of this primitive group. _Anchisaurus_ certainly belongs to
it.]
[Footnote 6: It is evidently "the dinosaur" of Sir Conan Doyle's "Lost
World" but the vivid description which the great English novelist
gives of its appearance and habits, based probably upon the Hawkins
restoration, is not at all in accord with inferences from what is now
known of these animals. See p. 44.]
[Footnote 7: Allosaurus, a carnivorous Dinosaur, and its Prey. By W.D.
Matthew. Am. Mus. Nat. Hist. Jour. Vol. viii, pp. 3-5, pl. 1.]
[Footnote 8: The cost of preparation is now defrayed by the Museum.]
[Footnote 9: Tyrannosaurus, Restoration and Model of the Skeleton. By
Henry Fairfield Osborn. Bull. Amer. Mus. Nat. Hist., 1913, vol. xxxii,
art. iv, pp. 91-92.]
[Footnote 10: Since these lines were written the Museum has secured
finely preserved skeletons of two or more kinds of Carnivorous
Dinosaurs from the Belly River formation in Canada.]