CLASS REPTILIA. 113 



is used as a tactile (tak'til) organ. Poisonous snakes have 

 fangs, long lance-like teeth, occupying the anterior of the 

 upper jaw. They are grooved, or tubed, leading from 

 glands situate in the roof of the mouth and opening by 

 a narrow slit at their extremity, that the poison, when 

 they " strike," may be placed well into the wound. Though 

 capable of feeling any unusual jar, as that made by 'an 

 approaching animal, external ears are not present. The 

 epidermis of serpents is shed at regular intervals, cleav- 

 ing away from the lips at first, and being turned inside 

 out as the animal leaves it. When the snake is in good 

 health, the skin thus sloughed is entire, even the cover- 

 ing of the lidless eyes being intact. Though many ser- 

 pents deposit their eggs, others, especially the poisonous 

 forms, hatch the eggs in their own bodies, being ovovi- 

 viparous. The winter is passed in hibernation, several 

 species congregating in the fall, and coiling together in a 

 mass. All our more common snakes are 



FIG. 194. 



quite harmless, being destitute of fangs, 

 and of too small size to occasion any 

 thing but fright. 



The Green, Striped, Black, Water, Eutae'ma sir 1 tails. 



j T> JM 07 Striped Snake. 



and Puffing Snakes are also members 



of this harmless class, as is also the so-called "Adder." 



The Boas of the New and the Pythons of the Old World, 

 are also without poison apparatus. These are the largest 

 Ophidians, though they seldom exceed a length of fifteen 

 feet. They are found in the tropics, often near some 

 pool, over which they suspend themselves, being aided 

 in this by their rudimentary hind limbs, which appear 

 at the base of the tail as a pair of spurs. When an ani- 

 mal, like a small dog, for instance, comes to drink, the 

 reptile seizes and cjuickly wraps several coils of its body 



