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T. trigonocephalus, Merr. Tent., p. 156. 

 Nigromorginatus, Kuhl. Beit., p. 20. 

 Megcera olivacea, Gray. Zool. Mis., p. 49. 

 The anal is entire, but the ventral in front of it is notched or 

 divided. Two pairs of shields on the snout, the inner twice the 

 size of the outer. Scales in 17 — 19 rows, slightly keeled on the 

 back, the others smooth. Ventrals 147 — 152. Caudals 57 — 63. 

 Colour green, with network of black stripes on the head, one 

 running from the eye to the gape. A black vertebral band emit- 

 ting black streaks on either side alternately. The black is mar- 

 gined with yeUow, and the streaks have usually a yellow centre. 

 Sides slightly tinged with yeUow. Ventrals pale green, with a 

 broad posterior yellow margin. Caudals marbled with blackish, 

 and tail tip black. 



Grows to 31 inches. (Tail 5.) 

 Inhabits Ceylon. 



b. Shield in front of the facial pit divided from the 

 second upper labial. 



T. mutabilis, Stol. J. A. S. B., 1870, p. 219. . 



Body slender. Scales in 21 rows. The second upper labial 

 sometimes forms the anterior margin of the facial pit, or is some- 

 times divided into two, even on opposite sides of the same speci- 

 men. Anal entire. Ventrals 156 — 167. Subcaudals 48 — 62. 

 Supranasals separated by a single shield. The first labial united 

 to the nasal and marked with a groove only. One row of scales 

 below the infraocular. Colour very variable. On the head 

 blackish brown, on the body olive brown, barred with numerous 

 greenish white dark-edged cross bands, either regular or broken 

 and alternating. A white streak from the rostral to the gape, 

 meeting a temporal streak, and thence continued along the edge 

 of the ventrals as a line of white and brown spots. Two other 

 bands down each side separated by a brown band. Below yel- 

 lowish or greyish, densely marbled with dark and red, especially 

 in front. Tail coral red or reddish brown, darker below. 



Grows to 19-50 inches. (Tail 275.) 



Inhabits the Andaman and Nikobar Islands. 



