10. ANCISTRODON. 519 
10. ANCISTRODON. 
Agkistrodon, Palisot de Beauvois, Tr. Am. Philos. Soc. iv. 1799, 
. 881; Baird § Gir. Cat. N. Am. Rept. p. 17 (1853) ; Stejneger, 
ep. U.S. Nat. Mus. f. 1893, p. 401 (1895). 
Scytale, part., Latr. Hist. Rept. iii. p. 158 (1802); Daud, Hist. 
Rept. v. p. 334 (1803). 
Cenchris, Daud. t. c. p. 356; Wagl. Syst. Amph. p. 175 (1830) ; 
Gray, Zool. Misc. p. 50 (1842), and Cat. Sn. p. 15 (1849). 
Cophias, part., Merr. Tent. Syst. Amph. p. 154 (1820). 
Trigonocephalus (non Opp.), Kuhl, Isis, 1822, p. 473; Fitzing. N. 
Classif. Rept. p. 34 (1826); Wagl.l. c.p.1738; Gray, Ul. ec. pp. 50 
& 14; Dum. & Bibr. Erp. Gén. vii. p. 1488 (1854); Jan, Elenco 
sist. Ofid. p. 124 (1853) ; Strauch, Schl. Russ. R. p. 232 (1873). 
Tisiphone, Fitzing. 1. c.; Peters, Mon. Berl. Ac. 1862, p. 673. 
Acontias (non Cuv.), Troost, Ann. Lye. N. York, iii. 1836, p. 176. 
Toxicophis, Troost, l. c. p. 190; Bard § Gir. 1. c. p. 19. 
Trigonocephalus, part., Schleg. Phys. Serp. ii. p. 527 (1887). 
Halys, Gray, Cat. p. 14; Peters, 1. c. p. 671; Giinth. Rept. Brit. 
Ind. p. 392 (1864). 
Hypnale, Gray, J. c. p. 15; Peters, l. c. p. 673; Giinth, 1. ¢. p. 894. 
Leiolepis (non Cuv.), Dum. §& Bibr. Mém. Ac. Se. xxiii. 1853, p. 534, 
and Erp. Gén. vil. p. 1499. 
Ancistrodon, Baird, Serp. N. York, p. 13 (1854); Cope, Proc. Ac. 
Philad. 1859, p. 336; Peters, l. c. p. 671; Bouleng. Faun, Ind., 
Rept. p. 423 (1890); W. £. Taylor, Amer. Nat. 1895, p. 283. 
Calloselasma, Cope, Proc. Ac. Philad. 1859, p. 336; Giinth. 1. c. 
p. 391. 
Upper surface of head with the nine normal shields, or internasals 
and preefrontals broken up into scales. Body cylindrical; scales 
smooth or keeled, with apical pits. Tail moderate or short; sub- 
caudals single or in two rows. ; 
Borders of the Caspian Sea; Asia; North and Central America. 
Synopsis of the Species. 
I. Scales in 21-27 rows; internasals and prefrontals well deve- 
loped. 
A. Scales keeled. 
1. Anterior subcaudals single; second upper labial usually 
forming the anterior border of the loreal pit. 
a. Snout not produced. 
No loreal, upper preocular in contact 
with the posterior nasal; third upper 
labial usually entering the eye ; scales 
in 25 (rarely 27) rows; ventrals 130- 
147; subcaudals 33-51............ 1. piscivorus, p. 520. 
A loreal, separating the upper preeccular 
from the posterior nasal ; eye separated 
