THE AUSTRALIAN MUSEUM MAGAZINE. 



317 



with numerous keels, buttresses, and 

 struts, so as to combine the largest 

 possible surface with minimum w(>ight. 

 The rest of the vertebral column shows 

 the same features, but not in so pro- 

 nounced a degree. The ribs and limb 

 bones, on the contrary, were solid and 

 heavy, which has suggested the view 

 that these reptiles spent much of their 

 time under water, wading about on the 

 bottom of rivers or freshwater lagoons, 

 their massive limb bones counteracting 

 the buoyancy of their bodies, like the 

 lead in a diver's equipment, while their 

 giraffe-like necks enal)led them to thrust 

 their heads up from the depths like 

 the periscope of a submarine, to renew 

 their air supply and have a look round. 

 From the structure of their teeth the 

 conclusion is drawn that their food 

 consisted of succulent vegetation such 

 as grows in swamps and marshes. The 

 amphibious dinosaurs had apparently 

 no means of defence against possible 

 enemies, unless they were able to use 

 their long flexible tails as a sort of lash, 

 and it is probable that they were ac- 

 customed to seek safety by retreating 

 to the water. Some authors consider 

 that they never came ashore at all, 

 while others believe that they were 

 wholly land animals. Who knows ? 



the carnivorous dinosaurs (ther- 

 opoda). 



Compared with the amphibious dino- 

 saurs, the carnivorous types were much 

 more diverse in structure and size. 

 Some were no larger than a cat, and 

 Tyrannosaurus, with its length of forty- 

 seven feet, rivalled modern elephants 

 in bulk. They were armed with nu- 

 merous long sharp teeth and sharp 

 curved claws, and their general structure 

 indicates that they were active and 

 formidable beasts of prey. In apjiear- 

 ance they were a sort of cross between 

 a bird and a lizard, with long hind 

 legs on which they habitually walked, 

 their long tail balancing the weight of 

 their body ; the fore legs in forms such 

 as Tyrannosaurus, were almost ludi- 

 crously small in proportion, and quite 

 inadequate to support the body of the 

 animal. The skull cast of Tyranno- 

 saurus shown in the case, and the 

 photograph of the complete skeleton 

 in association with the human figures, 

 show that the reptiles, unlike the am- 

 phibious dinosaurs, had a large head, 

 as we should expect in a predatory 

 animal. Its brain, however, was small 

 compared with that of a modern croco- 

 dile or lizard, and probably Tyranno- 



Mounted Skeleton of Tyrannosaurus in the American Museum of Natural History. 

 This reptile was forty-seven feet long, the largest flesh-eating land animal that ever lived. 



[Cuurh'Ky lit the Aiwricaii Museum of Natural Hisitory. 



