EXTERNAL CHARACTERS 23 



b. Nostrils directed upwards ; internasals 

 much narrowed in front. 

 Scales in ig rows ; normally 2 pre- and 3 or 4 post- 

 oculars ; suboculars sometimes present ; usually 

 8 upper labials, fourth or fourth and fifth entering 



the eye; ventrals 160-187 ; subcaudals 48-79 



Tropidonotus tessellatus. 



Scales in 21 (rarely 19 or 23) rows ; normally 1 or 2 



pre- and 2 postoculars ; usually 7 upper labials, 



third and fourth entering the eye ; ventrals 



147-164; subcaudals 46-72. Tropidonotus viperinus. 



2. Dorsal scales smooth or feebly keeled; 



normally a single loreal. 



a. Two or three superposed anterior tem- 

 porals (very rarely one) ; nostril usually 

 between two nasals. 

 a. A subocular below the preocular. 

 * Scales smooth, in 17 or 19 rows. 

 Two upper labials entering the eye ; preocular not 

 in contact with the frontal ; scales with two apical 

 pits ; ventrals more or less distinctly angulate 



laterally, 160-230; subcaudals 87-131 



Zamenis gemonensis. 

 Two upper labials entering the eye ; preocular usually 

 in contact with the frontal ; scales with a single 

 apical pit ; ventrals very distinctly angulate later- 

 ally, 205-218 ; subcaudals 98-132. Zamenis dahlii. 

 ** Scales in 23 to 29 rows (usually 25 or 

 27), with two apical pits. 



