EXTERNAL CHARACTERS 27 



Snout pointed, with raised canthus ; rostral in con- 

 tact with a single apical shield ; 8 or 9 upper 

 labials; scales in 21 rows, rarely 19; ventrals : 



c? 130-148, ? 130-150 Vipera renardi. 



Snout truncate or broadly rounded, flat above or 

 with slightly raised canthus ; rostral in contact 

 with two apical shields, rarely with one ; 8 or 9 

 upper labials; scales in 21 rows, rarely 19 or 23; 



ventrals: c? 132-150, $ 132-158 Vipera bems. 



/3. Snout usually more or less turned up at 

 the end or produced into a scaly dermal 

 appendage ; supraocular not extending 

 posteriorly beyond the vertical of the pos- 

 terior border of the eye ; frontal and 

 parietals often absent or very small ; 

 2 or 3 series of scales between the eye and 

 the upper labials ; 9 to 13 upper labials ; 

 scales in 21 or 23 rows, rarely 19 or 25. 

 Snout simply turned up, the raised portion bearing 

 2 or 3 scales ; rostral not more than once and a half 

 as deep as broad; ventrals: 0*134-158, $ 141-169. 



Vipera aspis. 

 Snout simply turned up or produced into a small 

 appendage, the raised portion with 5 or 6 (rarely 3) 

 scales ; rostral i\ to 2 times as deep as broad ; 

 ventrals: o* I 25-i46, ? 135-147 ... Vipera I atastii. 

 Snout produced into an appendage covered with 

 10 to 20 scales ; rostral not reaching the summit 

 of the rostral appendage; ventrals: S 133-161, 

 ? 135-163 Vipera ammodytes. 



