200 MR. G. A. BOULENGER ON 



b. A deep groove on side of head, above the upper 



labials; scales smooth, in 23 rows Glypholycus. 



2. Pupil round ; 2 or 3 superposed anterior temporals ; scales in 21 rows or 



more ; ventrals 175 or more. 

 A deep groove between posterior nasal and praeocular ; scales 



keeled, in 23 rows Botlirophtludmus. 



No groove on side of snout ; scales smooth or very obtusely 



keeled, in 25 to 31 rows Pseudaspis. 



No groove on side of snout'; scales smooth, in 21 rows Coronella. 



3. Pupil vertically elliptic. 



a. Scales smooth, of vertebral row not enlarged ; subcaudals less than 73. 

 Scales in 25 to 33 rows; subcaudals single or paired Boodon. 



Scales in 15 or 17 rows ; subcaudals paired Lycophidium. 



b. Scales of vertebral row enlarged ; subcaudals 73 or more. 



Scales strongly keeled, vertebrals bicarinate, in 21 rows Gonionotophis. 



Scales strongly keeled, vertebrals bicarinate, in 15 or 17 rows. Simocephahis. 

 Scales smooth, in 15 rows; head very distinct fiom neck; 



eye large; body compressed Hormonotus. 



4. Pupil round ; body usually very slender (tree-snakes), with the scales 



in 13 to 19 rows. 



a. Scales in 13 or 15 rows, of vertebral row not enlarged. 



a. Lateral scales as long as dorsals ; colour green or black and green. 

 *# Scales smooth. 



Subcaudal shields not keeled Chlorophis. 



Subcaudal shields keeled and with a notch corresponding to 



the keel, same as on the ventrals Philothamnus. 



## Scales keeled. 

 Subcaudal shields keeled and notched ; a single anterior 



^ temporal Gastropyxis. 



Subcaudal shields not keeled ; usually two superposed anterior 



temporals Hapsidophrys. 



/3. Lateral scales much shorter than dorsals, which 

 are keeled; a single anterior temporal; eye 

 very large Thrasops. 



b. Scales in 17 or 19 rows, very narrow ; a single 



anterior temporal ; eye very large Rhamnopliis. 



5. Pupil round ; nostril in a single or semidivided nasal ; scales not oblique, 



short and smooth, in 15 to 19 rows. 



Nostril directed upwards, nasal semidivided; two superposed 



anterior temporals Grayia. 



Nostril lateral, nasal entire ; a single anterior temporal Homalosoma. 



B. Snout with angular horizontal edge. 

 Eye in contact with labials ; internasal and prefrontal single; 



scales in 15 or 17 rows ; ventrals less than 170 Prosymna. 



Suboculars separate the eye from the labials; scales in 19 to 



25 rows ; ventrals more than 170 Scapkiophis. 



II. No loreal, nasal in contact with praeocular ; pupil 

 vertically elliptic : scales strongly keeled, some of the 

 laterals very oblique Dasypeltis. 



1. Tropidonotus. 

 Kuhl, Bull. Sc. Nat. ii. 1824, p. 81 ; Bouleng. Cat. Sn. i. p. 192. 

 Two species : — 



Scales smooth, in 17 rows ; ventrals 119-135; anal entire (rarely 



divided) T.fuliginoides. 



Scales smooth, in 19 rows; ventrals 131-150; anal divided T. olivaceus. 



