524 VIPERID&. 
4. Ancistrodon acutus. 
Halys acutus, Giinth. Ann. § Mag. N. H. (8) i. 1888, p. 171, pl. xii., 
and in Pratt, Snows of Tibet, p, 242 (1892). 
Snout produced into a pointed dermal appendage directed for- 
wards, covered above by the internasals, beneath by a separate 
shield above the rostral, which is as deep as broad or deeper than 
broad; upper head-shields finely granulate ; frontal as long as or 
a little longer than the prefrontals, shorter than the parietals; 
upper preocular separated from the posterior nasal by a loreal ; 
one postocular and one subocular, separating the eye from the 
labials ; seven upper labials, second forming the anterior border of 
the loreal pit, third and fourth largest; three large lower tempo- 
rals, anterior largest. Scales strongly and tubercularly keeled, in 
21 rows. Ventrals 162-166; anal entire; subcaudals 538-60, 
mostly in pairs, 6 to 13 of the anterior single. Brown above, with 
blackish-brown X-shaped markings or alternating >-shaped ones ; 
head dark brown above, yellow on the sides, with a black streak 
from the eye to the angle of the mouth; yellowish beneath, spotted 
with dark brown and with a lateral series of large black blotches. 
Total length 1500 millim. ; tail 200, 
Upper Yang-tse, China. 
a-c. gd (V. 165, 166, Mountains North of A. E. Pratt, Esq. [C.]. 
162; C. 59, 60, 58). Kiu Kiang. (Types. 
d. 3 (V. 163; C. 58). Ichang. A. E. Pratt, Esq. [C.]. 
5. Ancistrodon halys. 
Coluber halys, Pall. Reise, iii. p. 703 (1776). 
Vipera halys, Pall. Zoogr. Ross.-As. iii. p. 49 (1811). 
Trigonocephalus halys, Licht. in Eversm. Reise Orenb, Buch. p. 147 
(i823) ; Eichw. Zool, Spec. iii. p. 170 (1831), and Faun. Casp.- 
Cauc. p. 128, pl. xix. (1841); Dum. § Bibr. vii. p. 1495 (1854) ; 
Strauch, Schl, Russ. R. p. 231 (1878); Jan, Icon. Gén. 46, pl. vi. 
fig. 1 (1874) ; Schret. Herp. Eur. . 182, fig. (1875) ; De Betta, 
tti Ist. Ven. (5) vi. 1880, p. 388 ; Boettg. in Radde, Faun. Flor. 
Casp. Geb. p. 74 (1886). 
—— caraganus, Lichw. Zool. Spec. iii. p. 170. 
Halys pallasii, Giinth. Rept. Brit. Ind. p, 392 (1864); Blanf. Zool. 
E. Pers. p. 480 (1876). 
Snout obtusely pointed, slightly turned up at the end, with obtuse 
canthus. Rostral as deep as broad or slightly broader than deep ; 
a pair of internasals and a pair of prefrontals; frontal as long as 
its distance from the end of the snout, as long as or a little shorter 
than the parietals; upper preocular separated from the posterior 
nasal by a loreal; one or two postoculars and a subocular ; loreal 
pit separated from the labials; three large temporals, anterior 
largest; 7 or.8 upper labials, third entering the eye. Scales 
sharply keeled, in 23 rows. Ventrals 149-174; anal entire; sub- 
caudals 31-44 pairs, Yellowish, greyish, reddish, or pale brown 
