144 STORY OF THE REPTILES 



All reptiles are hatched or born perfect and ac- 

 tive {precocial). There is no imperfect form, as in 

 amphibians and some fishes — not even as much as 

 there is in many birds and mammals. Even if their 

 eggs are broken open a little prematurely (before be- 

 ing just ready) the young will often escape open-eyed 

 and active at once, and survive. Little snakes and 

 others have a tiny hard shell or " pip " on their noses 

 — as in chickens — with which they cut the shells at 

 the proper time. 



With this large egg of the reptiles and the per- 

 fection of the young within it (not out of it) there 

 came in two membranes which enclose the young, 

 called the armiion and the allam,tois, but these are 

 connected with the nourishing and the breathing of 

 the little creature in a manner too technical for our 

 study. They are not foimd in any degree of perfec- 

 tion below the reptiles and the birds. 



In Hatching, the very beginning of the little rep- 

 tile is much the same as that of the amphibian and 

 fish, but each order soon hints its peculiar shape. 

 The turtle quickly shows its short body and shell 

 with the ribs free at first; the lizard-forms show 

 the limbs, and the snake its peculiar lithe form. In 

 no stage does the snake show any more sign of 

 limbs than it does in the adult — a fact which implies 

 that it has been for a long time only a snake. The 

 study of these developments is the science of embry- 

 ology — a whole realm of thought all by itself, which 

 has made some wonderful suggestions at kinships and 

 ancestors in all classes. 



