50 SAURIA. 



10. Their eggs have a cretaceous covering of greater or less firmness. 



11. The young animals undergo no metamorphosis. 



Remarks. Brogniart first established the order Sauria, and gave it accurate 

 and well defined limits; before his time, Linnaeus an-anged in the genus Lacerta, 

 not only all Lizards, but Salamanders and Tritons also. This order at present 

 includes nearly five hundred species, distributed in eight families. Of this great 

 mmiber only about fourteen diflcrent species have hitherto been fomid within the 

 limits of the United States. 



