﻿236 VIPERID^ 



Spain, in which, in addition to the peculiarities of 

 coloration mentioned in the description, the canthus 

 rostralis is frequently more distinctly raised, and the 

 frontal and parietal shields are often disintegrated 

 into scales; and the var. bosniensiSf Boettger, from 

 Bosnia, Carniola, and Carinthia, which is sometimes 

 very suggestive of, and has been taken for, the typical 

 form of V. aspiSf having like it, though not at all 

 constantly, two series of scales between the eye and 

 the labials, and the zigzag band replaced by a series 

 of dark bars across the back. The var. pseudaspts, 

 Schreiber, from the plains of Sclavonia, described 

 as straw yellow above, with narrow dark cross-bars, 

 is hardly separable from the var. bosniensis. 



Size, — Viper a berus is said to reach very excep- 

 tionally a length of 2 feet 11 inches. The largest 

 specimen in the British Museum (from Belgium) 

 measures 2 feet 3 J inches : the largest British 

 specimen 2 feet 3 inches. Both these specimens are 

 females. The largest male measures 2 feet 2 inches. 



Distribution. — Viper a berus ranges over the whole 

 of Northern Europe, to the extreme north of Scot- 

 land, and the sixty-seventh degree in Scandinavia, 

 and right across Northern Asia as far east as the 

 island of Saghalien. It is generally distributed in 

 Great Britain, occurring also on the Isles of Arran, 

 Islay, Skye, Lewis, and Mull, rare or absent in 

 some districts, common in others. Its distribution 

 in Central and Southern Europe is irregular. In 



