64 EXTINCT MONSTERS. 



by anatomists ; some concluding, with Professor Huxley, that 

 birds are descended from Dinosaurs ; while others, with Professor 

 Owen, consider the resemblance accidental, and in no way 

 implying relationship. Huxley has proposed the name Ornitho- 

 scelida, or bird-legged, for these remarkable reptiles. 



Dinosaurs must have formerly inhabited a large part of the 



primaeval world ;_for thejr r^r^H^^-^Q^-JbL.riQLg 11 ^ m 

 but in Africa, India, America, and even in 



*"" 



geologist finds that they reigned supreme on the earth throughout 

 the wTioie of ihe great Mesozoic era._^ 



Their bodies were, in some cases, defended by a formidable 

 coat of armour, consisting of bony plates and spines, as illustrated 

 by the case of Scelidosaurus (p. 105), thus giving them a 

 decidedly dragon-like appearance. The vertebrae, or bony seg- 

 ments of the back-bone, generally have their centra hollow on 

 both sides, as in the Ichthyosaurus ; but in the neck and tail they 

 are not unfrequently hollow on one side and convex on the 

 other. In some of the largest forms the vertebrae are excavated 

 into hollow chambers. This is apparently for the sake of 

 lightness ; for a very large animal with heavy solid bones would 

 find it difficult to move freely. In this way strength was combined 

 with lightness. 



All the Dinosaurs had four limbs,, and in many cases the hind 

 pair were very large compared, to the fore limbs. They varied 

 enormously in size, as well as in appearance. Thus certain of 

 the smaller families were only two feet long and lightly built ; 

 while others were truly colossal in size, far out-rivalling our j 

 modern rhinoceroses and elephants. 



The limbs of Cetiosaurus, for example, or of Stegosaurus, 

 remind us strikingly of those of elephants. The celebrated Von 

 Meyer was so struck with this likeness that he proposed the name 

 Pachypoda for them, which means thick-footed. Professor Owen 

 opposed this name ; for it was misleading, and only applied to 

 a few of them. He therefore proposed the name we have already 



