472 VIPERID2. 
shield. Body cylindrical; scales keeled, with apical pits, in 19-31 
rows; ventrals rounded. Tail short; subcaudals in two rows. 
« Europe, Asia, North and Tropica] Africa. 
Synopsis of the Species. 
I, Supraocular shield large, bordering the eye; scales on crown 
and snout smooth or faintly keeled; nostril in a single or 
irregularly divided nasal, which is separated from the rostral 
by a naso-rostral; scales in 19-23 rows (very rarely 25); . 
ventrals 120-169. 
A. Snout not turned up at the end ; supraocular usually extending 
posteriorly beyond the vertical of the posterior border of the 
eye; frontal and parietal shields usually well developed ; 
usually a single series between the eye and the labials, 
rarely two. 
Snout obtusely pointed, flat above, or 
with the canthus slightly raised; 
rostral usually in contact with a 
single apical scale, rarely with two; 
6 to 9 upper labials, usually 7 or 8; 
scales in 19 rows, rarely 21; ventrals : 
3d 120-135, 9 125-142.......... 1. ursinii, p. 473. 
Snout pointed, with raised canthus ; 
rostral in contact with a single apical 
scale; 8 or 9 upper labials; scales 
in 21 rows, rarely 19; ventrals: ¢ 
130-148, 9 130-150 ............ 2. renardi, p. 475. 
Snout truncate or broadly rounded, flat 
above or with very slightly raised 
canthus; rostral in contact with two 
apical scales, rarely with one; scales 
in 21 rows, rarely 19 or 23 ; ventrals: 
6 132-150, 9 182-158 .......... 3. berus, p. 476. 
B. Snout usually more or less turned up at the end or produced 
in a scaly dermal appendage; supraocular not extending 
posteriorly beyond the vertical of the posterior border of 
the eye; crown usually covered with small scales, frontal 
and parietals, however, sometimes well developed ; two or 
three series of scales between the eye and the labials; 9 to 
13 upper labials ; scales in 21-23 rows, rarely 19 or 25. 
Snout simply turned up, the raised por- 
tion bearing two or three (apical) 
scales; rostral not more than once 
and a half as deep as broad ; ventrals : 
d 134-158, 9 144-169.......... 4, aspis, p. 481, 
