& HALF-HOURS IN THE GREEN LANES. 



tang (I). This latter is a tooth in the form of a tube, 

 much longer than the other teeth, and curved (d). 

 It is placed in the upper jaw, one on each side of the 

 mouth. On the outer surface of the fang, near the 

 apex, is an elongated opening or slit (e), from which 

 a canal passes through the hollow in the interior of 

 the tooth, and is united to the duct which communi- 

 cates with the poison-gland. These fangs fall back- 

 wards, and lie concealed in a groove in the gum when 

 not in use. 



When a viper is struck, it first coils itself up, 

 leaving its head in the centre, or at the summit of 

 the coil, and drawn a little back, as if for the purpose 

 of reconnoitering. The animal then speedily uncoils 

 itself like a spring. Its body is next launched out 

 with such rapidity that for a moment the eye cannot 

 follow it. In this movement the viper clears a space 

 nearly equal to its own length ; but it never leaves 

 the ground, where it remains supported on its tail 

 or posterior portion of the body, ready to coil itself 

 up again and aim afresh a second blow, if the first 

 should fail. To do this the viper distends its mouth, 

 draws back its fangs, arranges them in the right 

 direction, and then plunges them into its enemy 

 by a blow of the head or upper jaw after which 

 the fangs are withdrawn. The lower jaw, which is 

 closed at the same moment, serves as a point of 

 resistance, and favours the entrance of the poison- 

 fangs; but this assistance is very slight, am'd tho 

 reptile acts by striking rather than biting. 



