70 EXTINCT MONSTERS. 
Professor Marsh and his comrades, in the far west of America, as 
well as by the researches of English geologists, assisted by the 
labours of many ardent collectors of fossils, in this country. Some 
of these may now be briefly considered. 
In Plate V. we have endeavoured to give some idea of a 
huge thigh-bone (femur) belonging to the truly gigantic Dinosaur 
called Atlantosaurus. It is six feet two inches long, and a cast 
of it may be seen in the fossil reptile gallery of the British Museum 
of Natural History (Wall-case No. 3). It should be mentioned, 
however, that the original specimen is partly restored, so that its 
exact length to an inch or so is not quite certain. In our illustra- 
tion it is shown to be a little taller, when placed upright, than 
a full-grown man. Professor Marsh, the fortunate discoverer 
of this wonderful bone, calculates that the Atlantosaurus must 
have attained a length of over eighty feet! and, assuming that it 
walked upon its hind feet, a height of thirty feet ! 
It doubtless fed upon the luxuriant foliage of the sub-tropical 
forests, portions of which are preserved with its remains. Besides this 
thigh-bone, Professor Marsh has procured specimens of vertebrze 
from the different parts of the vertebral column; but no skull or 
teeth. The vertebrze are hollowed out much in the same way as 
those of Brontosaurus. The fore limbs were large, as in the latter 
animal ; and the extremities of the limbs were provided with claws. 
Taking all present evidence, it appears that the Atlantosaurus 
bore a general resemblance to its smaller contemporary. We can 
therefore form a fairly good idea of its aspect and proportions. 
The same Jurassic strata from the Rocky Mountains’ have 
yielded remains of another big Dinosaur, belonging to the same 
family. This genus, which has been named the Apatosaurus, is 
represented by a nearly complete skeleton, in the Yale College 
Museum ; and is fortunately in an excellent state of preservation. 
Another species, of smaller size, though not so complete, adorns 
the same collection. This was about thirty feet long, and is 
known as Apatosaurus grandis. 
