1 42 EXTINCT MONSTERS. 



twenty feet radius above the water. Then plunging into the 

 depths, naught would be visible but the foam caused by the dis- 

 appearing mass of life. Should several have appeared together, 

 we can easily imagine tall, flexible forms rising to the height of the 

 masts of a fishing-fleet, or like snakes twisting and knotting them- 

 selves together. This extraordinary neck for such it was rose 

 from a body of elephantine proportions. The limbs were 

 probably two pairs of paddles, like those of Plesiosaurus, from 

 which this diver chiefly differed in the arrangement of the bones 

 of the breast. In the best-known species twenty-two feet 

 represent the neck in a total length of fifty feet. This is Elas- 

 mosaurus platyurus (Cope), a carnivorous sea-reptile, no doubt 

 adapted for deeper waters than many of the others. Like the 

 snake-bird of Florida, it probably often swam many feet below the 

 surface, raising the head to the distant air for breath, then with- 

 drawing it, and exploring the depths forty feet below, without 

 altering the position of its body. From the localities in which 

 the bones have been found in Kansas, it must have wandered 

 far from land ; and that many kinds of fishes formed its food 

 is shown by the teeth and scales found in the position of its 

 stomach." 



But to return to the sea-serpents. Mosasaurus is now known 

 to have been a long slender reptile, with a pair of powerful 

 paddles in front, a moderately long neck, and flat pointed head. 

 The tail was very long flat and deep like that of a great eel. 

 Mosasaurus princeps is computed to have been seventy-five to 

 eighty feet long. Clidastes was another genus of long and slender 

 shape, one species of which reached a length of forty feet. Some 

 forms of sea-serpent had sclerotic plates in the eye, such as we 

 found in the fish-lizard, or Ichthyosaurus (p. 46), but the 

 announcement that their bodies were protected by bony plates 

 has turned out to be a mistake, and the supposed plates really 

 belonged to the eye. 



Leiodon proriger (Cope) was abundant in the old North 



