150 EXTINCT MONSTERS 



and formidable skulls possessed by some other forms to be 

 described further on. But it is clear that no animal with such 

 a long neck as this creature had could have borne the weight 

 of a heavy skull. Short thick necks and heavy skulls always 

 go together. Indeed, the weight of the long neck itself would 

 have been serious had it not been for the fact that the vertebrae 

 in this part of the skeleton, and as far as the region of the tail, 

 have large cavities in the sides of the centra. This cavernous 

 structure of the vertebrae gradually decreases towards the tail. 

 The cavities communicated with a series of internal cavities 

 which give a kind of honeycombed structure to the whole 

 vertebras. This arrangement affords a combination of strength 

 and lightness in the massive supports required for the huge 

 ribs, limbs, and muscles, such as could not have been provided 

 by any other plan. (See Fig. 51.) 



The body of the Brontosaur was comparatively short, with a 

 fairly large paunch (see restoration, Plate XIX.). The legs and 

 feet were strong and massive, and the limb-bones solid. As 

 if partly in order to balance the neck, we find a long and power- 

 ful tail, in which the vertebras are nearly all solid. In most 

 Dinosaurs the fore limbs are small compared to the hind limbs 

 e.g. Megalosaurus, Iguanodon, and Scelidosaurus, but here we 

 find them unusually large. In this case, then, it is hardly 

 possible that the creature walked upon its hind legs, as many 

 of the Dinosaurs did. There can be little doubt but that many 

 other fierce and formidable Dinosaurs were living at the same 

 time and in the same region with Brontosaurus, whose remains 

 are found in the Jurassic rocks of Colorado (Atlantosaurus beds). 



How this apparently helpless and awkward animal escaped in 

 the struggle for existence it is not easy to conjecture ; but since 

 there is reason to believe it was more or less at home in the 



