52 



of praefrontals; frontal as broad as long, pentagonal; one prae- 

 and one postocular; temporals i + 2; twelve upper labials, 

 last two smallest, third to tenth separated from the edge of 

 the mouth by small trigonal scales and from the orbit by 

 three suboculars ; the ten anterior labials separated from the 

 shields above them by a longitudinal groove; posterior chin- 



Fig. 29. Opistliotropis riigosa (Lidth). Nat. size. Side view of head. 



shields separated by two scales. Scales in 17 rows, strongly 

 keeled and striated; ventrals 170; anal divided; subcaudals 95. 



Olive above, the scales white-edged; anterior upper labials 

 and outer row of scales yellow. Lower surface yellow. Length 

 of head and body 343 mm.; tail 130 mm. 



Type-specimen examined in the Leiden Museum. 



Habitat: Sumatra (Kaju tanam !). 



2. Opisthotropis typica (Mocq.). 



Helicopsoides typhus^ Mocquaid, Le Natural. 1890, p. 154; Nouv. Arch. Mus. 



(3) II 1890, p. 141, pi. IX, fig. 3. 

 Opisthotropis typica^ Boulenger, Cat. Sn. I 1893, p. 285. 



Snout short and broad, depressed; rostral twice as broad as 

 deep; nasals partly divided, in contact behind the rostral; 

 internasals small, triangular; praefrontal single or double ; frontal 

 large, as long as broad, pentagonal; supraocular very small; 

 loreal long, divided or partly divided ; two prae- and two 

 postoculars; temporals i + i + 2; eleven upper labials, separated 

 from the orbit by three suboculars, six anterior, twice as deep 

 as long, four last divided. Scales in 19 rows, keeled and 

 striated; ventrals 174 — 184; anal divided; subcaudals y6 — 85. 



