26lO 



SCALED REPTILES 



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. 



Under this title may be included the members of the lareest g-enus 

 Typical Pit , Al , , ., , . , . ... 



' of 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, characterized 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 



RAT-TAILED PIT VIPER. 



(One-sixth natural size.) 



two rows of shields on its lower surface. In all the Asiatic species there are two 

 rows of these subcaudal shields, and it is only in a few of the New- World forms 

 that they are reduced to a single series. The number of longitudinal rows of 

 scales on the body is very variable in the different species, ranging from as few as 

 thirteen to as many as thirty-one. In Asia these snakes range from India to the 

 south of China and the Liu-Kiu islands; and while some species are terrestrial and 

 normally colored, others are arboreal, and in the greenish tints assimilate to the 

 color of their surroundings. The climbing tree viper ( Trhneresurus gramineus) 

 belongs to a group of four allied Indian and Burmese species, characterized by their 



