THE VIPERS 



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quently nearly black. In some examples the under parts are lead color, with lighter 

 or darker spots, while in others they are almost wholly black. Bell records a speci- 

 men in which the ground color was nearly white and the markings black; and in 

 one variety the ground color is brick red, with ferruginous markings; while in a 

 second the under parts acquire a more or less marked blue tinge; and in a third the 

 whole skin, with the exception of that beneath the jaw and throat is black, the 

 usual markings being visible in certain lights. The average length of the common 

 viper is about ten inches. Its geographical distribution is greater than that of 

 any other European snake, extending from Portugal eastward to the island of 

 Saghalien, while northward it reaches to the Arctic Circle, and southward to Central 

 Spain. 



LONG-NOSED OR SAND VIPER. 



( One-half natural size. ) 



In Southwestern Europe the commdn viper is replaced or accom- 

 panied by a closely -allied form which may be called the southern 

 viper ( V. aspis} , regarded by some writers as a distinct species, and by others as a 

 mere variety. As it was doubtless to this snake that the Latin term Vivipara was 

 applied, German writers restrict the name viper to the southern form, and use the 

 term Kreuzotter for the common viper. In the latter the front of the upper surface 

 of the head is covered with three distinct small shields, but in the southern form it 



