242 VIPERID^E 



Four (rarely five) lower labials in contact with the 

 single pair of chin-shields. 



Scales in twenty-one or twenty-three (rarely nine- 

 teen or twenty-five) rows, with two apical pits, 

 strongly keeled, those of the outer row more or less 

 distinctly keeled, rarely perfectly smooth. Ventral 

 shields 134 to 158 (usually 143 to 153) in males, 

 141 to 169 (usually 145 to 157) in females; anal 

 entire ; subcaudals 32 to 49 (usually 37 to 45) in 

 males, 30 to 43 (usually 32 to 38) in females ; the 

 terminal caudal shield is sometimes shorter and less 

 spine-like than in V. berus, quite obtuse in some 

 specimens. 



Coloration. — Grey, greyish-brown, brown, reddish- 

 brown, coppery red, or orange, is the ground colour 

 in individuals from the same district; in this 

 respect sexual differences are less marked than in 

 the preceding species, red or copper-coloured speci- 

 mens being found in both sexes, and silvery white 

 specimens do not seem ever to occur. In rare cases 

 markings are entirely absent. In specimens from 

 the greater part of France, Italy, and the Southern 

 Tyrol (see Plate XIII.), the dark brown or black 

 markings on the body are mostly in the form of 

 narrow cross-bars, continuous across the back or 

 broken on the vertebral line and often alternating 

 with each other and with similar bars on the sides, 

 thus producing a pattern not unlike that frequently 

 found in Tropidonotus natrix ; a narrow dark line 



