346 



THE SNAKES OF SOUTH AFRICA. 



thus forcing the maximum amount of venom into the punctures. 

 Many snakes, such as the Ringhals Cobra and Boomslang, hang 

 on and worry the flesh if allowed. 



Inserted into the tough fibrous capsule of the poison glands 

 arc some of the fibres of the masseter muscles. The instant the 

 snake bites, these muscle fibres contract powerfully, and the 

 gland is wrung after the manner of twisting and wringing a wet 

 rag to remove its moisture. A comparatively large lymph space 

 surrounds the gland, and so permits of this wringing. The 



Fig. 139. — The sheathed fangs of a PuS Adder. When lying back in this position they are 

 enveloped by a protecting membrane or sheath known as the Vagina dentis. 



temporal and pterygoid muscles also aid in compressing the 

 poison glands. The venom which is stored up in the numerous 

 little cavities within the glands is thus driven with considerable 

 power into the channels or conducting tubes which communicate 

 with the bases of the hollow or grooved fangs. It rushes down 

 the grooved or hollow fangs and issues out in two fine streams. 



The bringing together of the end of the poison duct with the 

 hole at the base of the fang is completed with marvellous exact- 

 ness. By a wonderful arrangement of muscle-fibres, the harder 

 the snake presses his jaws when biting, the tighter does the 



