188 
ON THE PHYSIOGNOMY OF SEEPENTS. 
borders are garnished with plates ; 9 labial plates. S, 
188 + 53. 27 rows of scales, lanceolate, and strongly 
carinated. Olive-brown, usually varied by broad bands 
or lozenge-shaped spots. Inhabits the forests of Brazil. 
2. Trigonocephalus atrox. — Very analogous to the 
preceding, which it appears to represent in Guyana ; but it 
has 8 labial plates, 4 pairs of geneials, a more conical 
muzzle, scales less narrow, and less strongly carinated ; 
it has clear tints, verging to greyish purple. S. 194 + 64. 
3. Trigonocephalus lanceolatus. — Keplaces the two 
preceding in the smaller Antilles, and is much allied to 
them, but it has more numerous abdominal plates ; colours 
verging to green, or to yellow ; has two pairs of very small 
geneial plates, and has 31 rows of still smaller scales. 
S. 255 + 64. 
4. Trigonocephalus biline atus. — ^Very recognisable 
by its thin tail, susceptible of being coiled inwards, by its 
very compressed, slender trunk, and by its narrow belly, 
by its small scales, and, finally, by its beautiful green co- 
lour, passing to reddish brovm on the tail, and relieved by 
a ray of lemon-yellow near the abdomen. Above of a 
whitish-yellow. S. 280 + 78. 29 rows of scales. Very 
rare, in Brazil and in Cayenne. 
5. Trigonocephalus nigromarginatus. — A species of 
small size, well characterized by its lozenge scales, smooth, 
and disposed in 19 rows, larger on the summit of the head, 
by 2 broad plates at the tip of the muzzle, by divided su- 
perciliary plates, &c. S. 137 + 56. Above dark green, 
varied with black spots. Comes from Ceylon. 
6. Trigonocephalus Wagleri. — Head very wide and 
thick ; muzzle angular at the sides and obliquely trun- 
cated downwards ; 5 pairs of very squat geneials ; 25 rows 
of scales provided with strong keels, prolonged to a point 
under the throat. Above deep green, with transverse yel- 
low bands. S. 140 + 48. Inhabits the Island of Su- 
matra. 
7. Trigonocephalus viridis. — ^Middle sized ; above 
uniform green ; below yellow ; two large plates at the tip 
of the muzzle, which descends almost perpendicularly ; 
