NATURAL HISTORY. 



-<K)J<KOO- 



REPTILES. 



AMONG the living forms the reptiles are distinct, and it is easy to frame 

 a definition which will at once include all its members, and at the 

 same time exclude all that do not belong to the group ; but if we take the 

 forms which existed in past times into account, and which are known to us 

 from the fossils in the rocks, the problem is at once extremely complicated. 

 We then find on the one hand forms which intergrade with the birds, 

 while on the other certain forms show a strong relationship with the 

 Batrachia. 



Snakes. 



Most degenerate among the reptiles are the serpents, -or snakes, animals 

 which inspire the ordinary mind with feelings of horror or disgust. The 

 long, legless body, the expressionless eyes, the cold, clammy feeling, the 

 poisonous qualities of many species, and a remembrance of " the serpent," 

 are all elements which contribute to this revulsion. Yet there is an inter- 

 esting side to serpent life. Many are interesting in their habits, while 

 many others are among the most beautifully marked objects to be found 

 in nature. In all, the body is covered with scales, and the head with larger 

 plates. Only some of the boas have any traces of limbs. They move 

 with great rapidity by means of the broad scales on the lower surface of 

 the body, each of which acts like a foot, forcing the body along, and then 

 being moved forward to take a new foothold. At irregular intervals 

 snakes shed their skins. At the proper time it splits around the margin 

 of the mouth, and then the snake, by its contortions, or by passing between 

 two sticks or stones, gradually works out of the old integument, leaving it 

 entire, except for the opening at the mouth, but turned inside out. The 

 whole is much like drawing a stocking from the foot, and so thorough is it, 

 that even the thin cuticle covering the eyes is removed with the rest. 



A much-disputed question is that as to whether snakes swallow their 



