258 BIG ANIMALS 



existence of big animals in any particular deposit, we may 

 take it for granted, I think, that that deposit was laid 

 down under conditions unfavourable to the preservation of 

 the remains of large species. For example, the sediment 

 now being accumulated at the bottom of the Caspian 

 cannot possibly contain the bones of any creature much 

 larger than the Caspian seal, because there are no big 

 species there swimming ; and yet that fact does not 

 negative the existence in other places of whales, elephants, 

 giraffes, buffaloes, and hippopotami. Nevertheless, we 

 can only go upon the facts before us ; and if we compare 

 our existing fauna with the fauna of Jurassic and Pliocene 

 times, we shall at any rate be putting it to the test of the 

 severest competition that lies within our power under the 

 actual circumstances. 



In the Jurassic age there were undoubtedly a great 

 many very big reptiles. ' A monstrous eft was of old the 

 lord and master of earth : For him did his high sun flame 

 and his river billowing ran : And he felt himself in his 

 pride to be nature's crowning race.' There was the 

 ichthyosaurus, a fishlike marine lizard, familiar to us all 

 from a thousand reconstructions, with his long thin body, 

 his strong flippers, his stumpy neck, and his huge pair of 

 staring goggle eyes. The ichthyosaurus was certainly a 

 most unpleasant creature to meet alone in a narrow strait 

 on a dark night ; but if it comes to actual measurement, 

 the very biggest ichthyosaurian skeleton ever unearthed 

 does not exceed twenty-five feet from snout to tail. Now, 

 this is an extremely decent size for a reptile, as reptiles 

 go ; for the crocodile and alligator, the two biggest existing 

 lizards, seldom attain an extreme length of sixteen feet. 

 But there are other reptiles now living that easily beat the 

 ichthyosaurus, such, for example, as the larger pythons or 

 rock-snakes, which not infrequently reach to thirty feet, 



