ENALIOSAUKIA OR SEA-SAUKIAXS. 



227 



ture is so wonderful, and whose size is so gigantic, that 

 we might well doubt they had ever lived, were it not that 

 their fossil remains exist in the greatest abundance and 

 in wonderful perfection. 



The Enaliosaurs are furnished with paddles for swim- 

 ming, and, like fishes, their vertebrae are concave at each 

 end ; and, excepting the Mosasaurs, which have their 

 teeth in sockets, they have their large teeth set in a 

 groove. 



The Ichthyosaurus is a genus of the Sea-saurians of 

 the Jurassic period, which are from ten to forty feet in 



FIG. 260. 



Ichthyosaurus. 







length, with the bony cavity for the eye nearly a foot in 

 diameter, and with jaws in some species nearly six feet 

 long, and armed with two hundred stout, conical teeth ! 



The Plesiosaurus is a genus of sea-saurians, ten to thirty 

 feet in length, which are characterized by a long snake- 



FIG. 261. 



Plesiosaurus. 



like neck having from twenty to forty vertebrae a small 

 head, and short body. 



The Discosaurus (Elasmosaurus platyurus, Cope) had 



