vi] DISTRIBUTION OF SELECTED GROUPS 103 



poison snakes are of considerable geographical im- 

 portance. 



Australia lias only Elapines, but in abundance. 

 America has Crotalines and Elaps. Africa has hooded 

 Elapines and abundance of vipers. Europe has now 

 only vipers, in former epochs also Elapines and 

 Crotalineg. The Indian countries alone are cursed 

 with members of all three groups. 



Elapinae, culminating in the hooded cobras, genus 

 Naja, which ranges all through continental Africa 

 and the whole of temperate and warm Asia. Other 

 genera in India and thence in Australasia down to 

 Tasmania, America has received, or developed, only 

 the genus Elaps with many species from the States 

 to Patagonia ; none in the Antilles. 



Crotalinae or Pit-vipers in the southern half of 

 Asia, from Asia Minor to Borneo and Japan and 

 throughout North and South America. Both the 

 chief genera Lachesis and Andstrodon exist in the 

 Old and New World. A further modification of 

 pit-vipers are the rattlesnakes proper, with present 

 headquarters in the South- Western States and Mexico, 

 whilst only one species, Crotalus terrificns, has entered 

 South America, now ranging from Arizona to Argen- 

 tina. 



Viperinae, vipers without a sensory pit between 

 nose and eye, all over Eurasia and Africa, respecting 

 Wallace's line like the hooded cobras. The efficiency 



