11. LACHEsIS. 551 
20. Lachesis cantoris. 
Trigonocephalus cantori, Blyth, Journ. As. Soe. Beng. xv. 1846, 
377 
Trimeresurus viridis, var. cantori, Blyth, Journ. As. Soc. Beng. xxix. 
1860, p. 110. 
labialis, Steindachn. Novara, Rept. p. 86, pl. iii. figs. 1 & 2 
(1867); Theob. Cat. Rept. Brit. Ind. p. 221 (1876). 
—— cantoris, Stoliczka, Journ. As. Soc, Beng. xxxix. 1870, p. 222, 
pl. xii. figs. 3 & 4; Theob. l. c. p.222; Bouleng. Faun. Ind., Rept. 
p. 428 (1890). 
Rostral as deep as broad; nasal divided ; upper head-scales very 
small, smooth, almost granular ; supraocular shields distinct, narrow, 
sometimes divided into two; usually one or two scales between the 
internasals, 16 on a line between the supraoculars ; two small post- 
oculars and a subocular, which is separated from the labials by two 
or three rows of scales; 13 upper labials, first confluent with nasal, 
second forming the anterior border of the loreal pit; third largest ; 
temporals small, feebly keeled. Scales rather feebly keeled, in 27 
to 31 rows. Ventrals 174-184; anal entire; subcaudals 55-76 
pairs. Pale brown or dull green above, with small dark spots; a 
whitish streak along the outer series of scales; whitish or greenish 
beneath, uniform or with the base of the ventrals dark ashy or 
blackish. 
Total length 1020 millim.; tail 140. 
Andaman and Nicobar Islands. 
a. 2 (Se. 31; V. 178; C. 61). Nicobars, 
21. Lachesis jerdonii. 
Trimeresurus jerdonii, Giinth. Proc. Zool. Soc. 1875, p. 233, pl. xxxiv.; 
Bouleng. Faun. Ind., Rept. p. 427 (1890). 
xanthomelas, Giinth. Ann. § Mag. N. H. (6) iv. 1889, p, 221, 
and in Pratt, Snows of Tibet, p. 241, pl. i. fig. A (1892). 
Rostral as deep as broad or a little deeper than broad; nasal 
divided ; upper-head scales very small, smooth, juxtaposed ; supra- 
oculars large, larger than the eye; one or more scales between the 
internasals, 7 to 9 on a line between the supraoculars ; one or two 
small postoculars and a subocular, which isin contact with the 
third labial, and usually separated from the fourth by a series of 
small scales; 7 or 8 upper labials, second forming the anterior 
border of the loreal pit, third and fourth large; a series of large, 
smooth temporals above the labials. Scales strongly keeled, in 21 
or 23 rows. Ventrals 164-188; anal entire; subcaudals 54—67 
pairs. Greenish yellow or olive above, mixed with black ; a dorsal 
series of transverse rhomboidal reddish-brown spots edged with 
black ; head black above, with symmetrical yellow markings ; upper 
lip yellow, with one or more black spots, that on- the second labial 
