6o 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 ancestiy 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, however, 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 of 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 at the end of the reptile-gallery 

 at Cromwell Road. 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. 



