3 



-\--\- Nostril lateral; 22 scales round the 



body 6. T. elberti p. 7. 



2. Snout with sharp edge. 



t Rostral extending to between the eyes. 7. T. muUiUnealus p. 7. 

 ft Rostral not extending to between 

 the eyes. 



1. Rostral three fifths the width of 



the head 8. Z". olivaceus p. 8. 



2, Rostral not quite half the width of 



the head 9- ^. lorenzi p. 8. 



c. Nasal cleft proceeding from the second 

 labial. 



1. Nasal completely divided. 



aa. Snout rounded; nostril lateral; scales 



in 26 rows 10. Z". kapaladua p. 9. 



^^. Snout with a sharp edge; nostril in- 

 ferior; scales in 24 rows 11. T. depressiccps p. 9. 



2. Nasal incompletely divided. 

 X Nostril inferior. 



a. Rostral 2^5 the width of the head, 

 extending nearly to the level of 



the eyes; 18 scales round the body. 12. T. conradi p. 10. 



b. Rostral large ; 22 scales round the 



body Y^. T. bipdrtitus p. 10. 



c. Rostral ^\^ the width of the head, 

 not extending to the level of ihe 



eyes; 22 scales round the body. 14. T. Jlorensis p. 10. 

 XX Nostril lateral. 



1.20 scales round the body; rostral 

 '/s the width of the head, extending 

 to the level of the eyes 15. T. leucoproctus p. 11, 



2. 22 scales round the body ; rostral 

 narrow, the upper portion '/s '^e 

 width of the head, extending nearly 



to the level of the eyes 16. T. Jlaviventer p. 1 1 . 



3. 26 scales round the body ; rostral 

 narrow, the upper portion '/a ^^^ 

 width of the head, extending to 



between the eyes or nearly so , . 17. T. nigroalbtis p. 12. 

 4.26 or 28 scales round the body; 

 rostral '/a ^^e width of the head, 

 not extending to the level of the 

 eyes 18. T. in'ulUri p. 12. 



