﻿78 EVOLUTION IN THE PAST 



South Africa, India, and North America. These strange 

 creatures had well-developed hind-limbs ; whilst their " arms" 

 were comparatively short. The latter, no doubt, were 

 chiefly used for seizing and holding prey ; and locomotion 

 was effected, somewhat in kangaroo fashion, on the hind- 

 limbs only. Facility for agile and speedy movement was 

 certainly afforded by the hollowness of the limb-bones 

 (Zanclodon, Euscelosaurus, Epicampodon), The animals 

 varied a good deal in size : some remarkable forms, with 

 bird-like skulls, must have stood between five and six feet 

 in height (Anchisaurus). 



The precise line of dinosaurian descent is unknown. All 

 the Triassic forms seem to have been carnivorous ; and 

 they haunted, no doubt, lake-banks and riversides ; and 

 victimised the tender and neglected offspring of amphibians 

 and also of fellow-reptiles. 



Dinosaurs, so far as is known, were the first bipeds to 

 appear on earth — the first creatures to stand and move 

 about in a fairly erect position. They come, in fact, within 

 Plato's special definition of a man — " a biped without 

 feathers." Dinosaurs, therefore, were not dreamt of in his 

 philosophy. 

 plesio- Other reptiles, now first in view and known as plesio- 



saurians saurians, betrayed no inclination to bipedalism ; and when 

 on land must have moved about in a somewhat laboured 

 manner. They were undoubtedly good swimmers, and when 

 afloat must have had an appearance such as swans, deprived 

 of feathers and suffering from stiff necks, would present* 

 They had probably descended from some forms that had been 

 more or less permanent land-dwellers. Possibly their remote 

 ancestors were some land-frequenting stegocephs of Car- 

 boniferous times. Terrestrial life, it would seem, had lost its 

 charm ; and these Triassic descendants were experimenting 

 in water, and possibly becoming experts in fishing. Many 

 of them were of small size ; but here and there creatures 

 were to be seen varying in length from four to six feet 

 (Lariosaurus, Nothosaurus). 



Plesiosaurians were much more developed in the next 

 Period : and it is interesting to note that these Triassic 



