ANCISTRODON.—BOTHROPS. 187 
Ground-colour brownish-olive, brown or black. Young and light-coloured indi- 
viduals have broad dark cross-bands, which are irregularly edged with white spots. 
The white spots are retained after the bands have disappeared, and are more numerous. 
on the lower part of the sides and abdomen than on the back. A white or yellow line 
runs from the rostral along the canthus rostralis and the superciliary edge to behind 
the angle of the mouth; a white or yellow band along the upper labials. Rostral 
with a vertical yellow or white band, continued on the chin. | 
Scales keeled, in twenty-three series. Ventrals 137; subcaudals 65, of which the 
posterior are double. Upper labials eight. 
BOTHROPS. 
Bothrops, sp., Wagler, Syst. Amphib. p. 174 (1830). 
Bothrops et Ophryacus, Cope, Bull. U. S. Nat. Mus. no. 32, 1887, p. 88. 
Two subgenera :— 
I. Scales of the superciliary margin erect. (Opuryacus.) . . . . - 1. B. undulatus. 
II. A broad superciliary scute. (Borurors.). . . . . - + + + + + 2 Bi atrox. 
1. Bothrops undulatus. 
Atropus undulatus, Jan, Rev. et Mag. Zool. 1859, p. 157. 
Ophryacus undulatus, Cope, Bull. U. 8. Nat. Mus. no. 32, p. 88. 
Hab. Mexico, Omilteme in Guerrero (H. H. Smith), Orizaba (Mus. Brit.), Vera Cruz, 
Actopam (Com. Geogr.), Oaxaca (Sallé). 
With one exception, the specimens I have examined are young, and of a dark brown 
coloration with the black dorsal markings mentioned by Jan. A row of whitish spots 
runs along the lower part of the sides. ‘This is also the coloration of a young specimen 
from Omilteme. However, an adult female from the same locality, 23 in. long, is of 
a yellowish-green colour, the scales being densely punctulated with black, and only 
outline traces of the black rhombic dorsal markings remaining. Lower parts yellowish, 
the posterior abdominal and the caudal scutes punctulated with black. 
2. Bothrops atrox. 
Coluber atrox, Linn. Mus. Ad. Fried. i. p. 38, t. 22. fig. 2. 
Bothrops atrox, Wagl. Syst. Amph. p. 174; Dum. & Bibr. Erpét. vii. p. 1507; Jan, Iconogr. Ophid. 
xlvii. t. 2; Cope, Journ. Ac. N. Se. Phil. viii. p. 151 (1875). 
Trigonocephalus atrox, Schleg. Ess. ii. p. 535, t. 19. figg. 5, 6. 
Craspedocephalus atrox, Fitz. N. Class. Rept. p. 61; Gray, Cat. Viper. Sn’ p. 6. 
Hab. Mexico, Orizaba (Sumichrast), Mirador and Tuxpan (Cope), Atoyac in Vera Cruz, 
Teapa in Tabasco (H. H. Smith), Tehuantepec (Swmichrast) ; British Honpuras, 
Stann Creek (Rev. J. Robertson); Guatemaua, Pacific Coast and Vera Paz, low 
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