THE FIUNCII'AL Sl'ECIES OF I'OISONOUS SNAKES 25 



Hnhitat : South-east France (Basses-Alpes) ; Italy (Abruzzi) ; 

 Istria ; Mountains of Bosnia ; Plains of Lower Austria ; Hungary 

 (environs of Buda-Pesth). 



Yipera berus (Cominon Viper, or Adder). 



Snout rounded, short and truncate : pupil vertically elongate ; 

 vertical diameter of the eyes equal to or greater than the distance 

 separating them from the mouth ; frontal and parietal shields dis- 



FiG. 21. — (/) Vipcru hcnis ; (i^) Vip<.'ra dspis : (3,4) Yipera (imniodytcs. 

 (Natural size.) 



tinct, the former as long as broad, usually shorter than the space 

 separating it from the rostral shield ; 6 — 18 scales round the eyes ; 

 one or rarely two series of scales between the eyes and the lips ; 

 nasal shield single, separated from the rostral by a naso-rostral 

 shield : temporal scales smooth. Body scales in 21 rows (excep- 

 tionally 19 or 23), strongly keeled ; 132 — 150 ventral shields ; 

 38 — 30 subcaudals. 



Colour very variable, grey, yellowish, olive, brown, or red above, 



