188 ON THE PHYSIOGNOMY OF SERPENTS. 



borders are garnished with plates ; 9 labial plates. S. 

 188-1-53. 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. Trigonocepiialus 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 piu'ple. S. 194 -t- 64. 



3. Trigonocepiialus lanceolatus. — Replaces 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 4-04. 



4. Trigonocephalus bilineatus. — 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 brown on the tail, and relieved by 

 a ray of lemon-yellow near the abdomen. Above of a 

 whitish-yellow. S. 280-f78. 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 v\'ith strong keels, prolonged to a point 

 under the throat. Above deep green, with transverse yel- 

 low bands. S. 140 -H 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 ; 



