246 



SNAKES. 



Water-Viper. 



Another well-known North American representative of the genus 

 that must come in for a brief share of attention is the water- viper (A. 

 piscivorus), which inhabits marshes, rivers, and lakes, and attains a length of 

 nearly five feet. From the preceding species it may be distinguished by the 

 presence of two small smooth supplemental shields behind the parietals, and of 

 numerous small scales between the hinder frontal and temporal shields. The colour 

 is very variable ; but in the majority of specimens, on a shining greenish grey 

 ground, there are a larger or smaller number of dark bands somewhat similar to 

 those of the copper-head. Always found in the neighbourhood of water, this 

 snake extends southwards from North Carolina over the whole of North. America 



CLIMBING PIT- VIPER (| nat. size). 



and westwards as far as the Rocky Mountains. Feeding chiefly upon fish and 

 frogs, it will also devour all animals that may happen to fall into the water and 

 are not too large for its maw ; while in the rice-fields it is the dread of the negroes. 

 Not only is the water- viper feared by man, but it is shunned by all animals 

 dwelling in or near water. 



Typical Pit- Under this title may be included the members of the largest genus 



Vipers. o f the subfamily, which is likewise common to Tropical America and 

 Asia, and is the last group of snakes that we have space to mention. These pit- 

 vipers are long-bodied snakes, characterised by the whole of the upper surface of 

 the triangular head being covered with scales instead of shields ; the tail, which is 

 frequently prehensile, ending in a sharp point, and having either one or two rows 



