84 EXTINCT MONSTERS 



The Plesiosaur presents, on the one hand, points of resem- 

 blance to turtles and lizards, on the other hand, to crocodiles, 

 whales, and, according to some authorities, even the strange 

 Ornithorhynchus. But it will be very long before its ancestry 

 can be made known. In the mean time we must put it in a 

 place somewhere near the fish-lizards, and leave posterity to 

 complete what has at present only been begun. It must, how- 

 ever, be borne in mind that some of the above resemblances are 

 purely accidental, and not such as point to relationship. Because 

 their flippers are like those pf a whale, it does not mean that 

 Plesiosaurs are related to modern whales. It only means that 

 similar habits tend to produce accidental resemblances just as 

 the whales and porpoises, in their turn, resemble fishes. To 

 make torpedoes go rapidly through the water, inventors have 

 given them a fish-like shape ; in the same way the early forms 

 of mammals, from which whales are descended, gradually adapted 

 themselves to a life in the water, and so became modified to 

 some extent to the shapes of fishes. 



The Pliosaurs, above mentioned, are evidently relations, but 

 with short necks instead of long ones. They had enormous heads 

 and thick necks. Fine specimens of their huge jaws, paddle- 

 bones, etc., may be seen in the fossil reptile-gallery at Cromwell 

 Eoad. One of the skulls exhibited there is nearly six feet 

 long, while a hind paddle measures upwards of six and a half 

 feet in length, of which thirty-seven inches is taken up by the 

 thigh-bone alone. The teeth at the end of the jaws are truly 

 enormous. One tooth, from a deposit known as the Kimmeridge 

 Clay, is nearly a foot long from the tip of the crown to the base 

 of the root. In some, the two jaw-bones of the lower jaw are 

 partly united, as in the sperm-whale or cachalot. Creatures so 

 armed must have been very destructive. 



