VIPERA 



253 



Var. mevidionalis, Boulenger : Naso-rostral shield 

 never reaching the canthus rostralis, and but rarely 

 extending higher up than the upper border of the 

 rostral, which is often as deep as broad or a little 

 deeper than broad; rostral appendage clad with 



p IG> ^g — Side Views of Heads of V. ammodytes typica (a) and 



Var. mevidionalis (b) 



a b c 



Fig. 40 — Front Views of End of Snout, showing the Lepi- 

 dosis. (From Proceedings of the Zoological Society, 1903) 



a, Form typica; b, var. mevidionalis ; c, var. montandoni 



fourteen to twenty scales, in four or five (rarely three) 

 transverse series between the rostral shield and the 

 apex. Supraciliary edge usually more prominent 

 than in the typical form, sometimes slightly angular. 

 Scales in twenty-one rows (very rarely twenty-three). 

 Ventral shields 133 to 147; subcaudals 24 to 35. 



