214 THE STORY OF THE EARTH AND MAN. 



rhinoceros, or tho swan to the porpoise. Two fisher- 

 men so variously and differently fitted for their work 

 it would be difficult to imagine. But these differences 

 were obviously related to corresponding differences in 

 food and habit. The Ichthyosaur was fitted to 

 struggle with the waves of the stormy sea, to roll 

 therein like modern whales and grampuses, to seize 

 and devour great fishes, and to dive for them into the 

 depths; and its great armour-plated eyes must have 

 been well adapted for vision in the deeper waters. 

 The Plesiosaur, on the contrary, was fitted for com- 

 paratively still and shallow waters; swimming near 

 the surface with its graceful neck curving aloft, it 

 could dart at the smaller fishes on the surface, or 

 stretch its long neck downward in search of those 

 near the bottom. The Ichthyosaurs rolled like por- 

 poises in the surf of the Liassic coral reefs and the 

 waves beyond ; the Plesiosaurs careered gracefully in 

 the quiet waters within. Both had their beginning at 

 the same time in the earlier Mesozoic, and both found 

 a common and final grave in its later sediments. 

 Some of the species were of very moderate size, but 

 there were Ichthyosaurs twenty five feet long, and 

 Plesiosaurs at least eighteen feet in length. 



Another strange and monstrous group of creatures, 

 the Elasmosaurs and their allies, combined the long 

 neck of Plesiosaurs with the swimming tail of Ichthyo- 

 saurs, the latter enormously elongated, so that these 

 creatures were sometimes fifty feet in length, and 

 whale-like in the dimensions of their bodies. It is 



