THE MESOZOIC AGES. 203 



kangaroo, but with tlow and stately tread, occasionally 

 resting, and supporting itself on the tripod formed 

 by its hind limbs and a huge tail, like the inverted 

 trunk of a tree. The upper part of its body becomes 

 small and slender, and its head, of diminutive size 

 and mild aspect, is furnished with teeth for munching 

 the leaves and fruits of trees, which it can easily 

 reach with its small fore-limbs, or hands, as it walks 

 through the woods. The outward appearance of 

 these creatures we do not certainly know. It is not 

 likely that they had bony plates like crocodiles, but 

 they may have shone resplendent in horny scale 

 armour of varied hues. But another and more dread- 

 ful form rises before us. It is Megalosaurus or perhaps 

 Lcelaps, Here we have a creature of equally gigantic 

 size and biped habits ; but it is much more agile, and 

 runs with great swiftness or advances by huge leaps, 

 and its feet and hands are armed with strong curved 

 claws ; while , its mouth has a formidable armature of 

 sharp-edged and pointed teeth. It is a type of a 

 group of biped bird-like lizards, the most terrible 

 and formidable of rapacious animals that the earth 

 has ever seen. Some of these creatures, in their 

 short deep jaws and heads, resembled the great car- 

 nivorous mamreals of modern times, while all in the 

 structure of their limbs had a strange and grotesque 

 resemblance to the birds. Nearly all naturalists re- 

 gard them as reptiles; but in their circulation and 

 respiration they must have approached to the mam- 

 malia^ and their general habit of body recalls that of 



