FRESH-WATER SNAKES. 227 



and viperish - looking as well, but are perfectly harm- 

 less. 



This is the snake to which almost this book owes its 

 origin, the specimens at the Zoological Gardens called 



* Moccasins ' tripping me up at the outset, as my preface 

 sets forth. Holbrooke describes it as spending most of its 

 time in the water, or about pond and river banks. It swims 

 rapidly, and hundreds may be seen darting in all directions 

 through the water. They are very common in the United 

 States, and might have formed the * wreathed myriads ' on 

 Lake Erie formerly. In summer they roost on the lower 

 branches of trees, overhanging the water, like TrigonocepJialus 

 piscivorus, the true 'water moccasin,' or 'cotton mouth.' 

 At the time of writing there are examples of both these at 

 the Gardens, the harmless ' moccasin,' a rather handsome 

 snake, and the venomous one (not there recognised as the 

 well-known moccasin of the United States), so nearly black 

 that we can account for its being occasionally called the 

 ' black water viper.' 



It is probably Tropidonotus which Parker Gilmore des- 

 cribes as 'water vipers." At Vincennes in Indiana, he says, 



* On the side where some alder bushes grow in the water, 

 I have seen, on a very warm and bright day, such numbers 

 of water vipers twined round the limbs and trunks which 

 margin the pond, that it would be almost impossible to 

 wade a yard without being within reach of one of them. 

 They certainly have all the appearance of being venomous ; 

 the inhabitants say, however, they are harmless. They feed 

 principally on fish, frogs, and small birds.' 



^ Prairie Farms and Prairie Folks, vol. ii. pp. 83, 84. 



