(5) _L. microphthalmus._--Snout short, rounded; eyes very small; 7 supralabials, of which the third and the sixth or seventh are the largest; scales in 23 rows, dorsals tubercularly keeled; 159-161 ventrals; 52-55 subcaudal pairs. Colour yellowish-brown or pale olive on the back, with dark brown triangles on the sides; posteriorly, the united triangles form cross-bands; a yellowish band from the eye to the side of the neck; belly dark brown with yellowish spots. Total length, 630 millimetres; tail 100. _Habitat_: Peru, Ecuador. (6) _L. pictus._--Snout obliquely truncate; two series of scales between the eye and the labials; scales in 21-23 rows, strongly keeled; 157-172 ventrals; 40-74 pairs of subcaudals. Colour pale brown, with a dorsal series of large black-edged brown spots, which may form a vertebral zigzag band; a black streak behind the eye, and a vertical bar below the eye; belly yellowish, spotted with brown. Total length, 310 millimetres; tail 43. _Habitat_: Peru. (7) _L. alternatus._--Head narrow, elongate; 8-9 supralabials; scales in 29-35 rows, very strongly keeled; 167-181 ventrals; 34-51 pairs of subcaudals. Colour brown, very elegantly marked with opposite or alternating pairs of large C-shaped markings, which are dark brown, edged with black and yellow, and separated by narrow interspaces of the ground colour; head dark·brown above, with a ⅄̅-shaped light marking, the transverse bar between the eyes; belly whitish, spotted with brown or black. Total length, 1,190 millimetres; tail 110. _Habitat_: Southern Brazil, Paraguay, Uruguay, Argentina. (8) _L. neuwiedii_ (known as the _Urutù_ in Brazil; fig. 70).--Snout obtusely pointed; supraocular large, separated from its fellow by 6-9 longitudinal series of scales; 8 or 9 supralabials; scales very strongly keeled, in 21-27 rows; 168-182 ventrals; 41-53 subcaudals. Colour yellowish or pale brown, with dark brown black-edged spots; the spots on the back form a single series or a double alternating series; a dark spot on the snout; a pair of dark bands from the vertex to the nape, and another from the eye to the angle of the mouth; belly yellowish, more or less powdered with brown. Total length, 770 millimetres; tail 120. _Habitat_: Brazil, Paraguay, Argentina. [Illustration: FIG. 70.--_Lachesis neuwiedii_ (known as the _Urutù_ in Brazil). (After Lacerda.)] (9) _L. ammodytoides._--Snout turned up, in the shape of a wart; two series of scales between the eye and the labials; scales in 23 or 25 rows, very strongly keeled; 149-160 ventrals; 30-38 pairs of subcaudals. Colour pale brown, with large brown black-edged spots or cross-bands, which may alternate and form a zigzag band; a dark streak behind the eye; belly yellowish, spotted with brown. Total length, 460 millimetres; tail 55. _Habitat_: North-eastern Patagonia and Argentina. (10) _L. xanthogrammus._--Head elongate, snout short; scales in 27 rows, feebly keeled; 196 ventrals; 54 subcaudals.