318 REPTILES OF THE WORLD 



gerous ; nevertheless they are poisonous enough to cause 

 occasional loss of human life ; among them are the com- 

 mon viper and the sand natter. 



Popularly described, the venom of the Viperine snakes 

 plays most of its havoc in the blood. The bitten arm 

 or leg swells greatly and becomes much discolored; 

 within the injured member the blood actually oozes from 

 the vessels, producing a remarkable state of internal 

 hemorrhage, this bringing great danger of attendant 

 septacaemia from germ infection and necessitating heroic 

 drainage. The bites of elapine snakes produce little 

 of these local effects. The poison appears to attack 

 the nerve centers, particularly that system controlling 

 the muscles of the chest, and the victim meets death from 

 an inability to breathe. It is in such cases that strych- 

 nine is a valuable alternative. 



The True Vipers; subfamily Viperince: Among the 

 members of the Viperince are some of the most villainous- 

 looking of all snakes; for the most part the head is 

 flattened and heart-shaped, the body short and thick, 

 but there are strange exceptions to the general form, as 

 will be found in all families of snakes. In tropical and 

 South Africa is a genus of vipers forming the most 

 deceptive series of snakes the writer has ever examined. 

 They are moderately slender with gradually-tapering 

 tail, have a very ordinary head bearing large, sym- 

 metrical shields, while the eye has a round pupil ; to add 

 to the deception, there is a loreal plate (between the eye 

 and the nostril) , as seen with the typical harmless snakes. 



The Cape Viper, Causus rhombeatus, may be taken 

 as a good example of this colubrine-like series. The 

 scales are keeled. Above, the color is grayish with dark 

 and angular, sometimes rhomb-shaped markings, these 

 often margined with white. If the mouth is examined, 



