SNAKES OF WEST AFRICA. 275 



3. Pupil vertically elliptic ; anal entire. 



a. Scales smootli, vertebral row not enlarged ; subcaudiils less than 75. 



Scales in 23 to 33 rows Boodon. 



Scales in 17 rows Lycophidium. 



h. Scales of vertebral row enlarged. 



Scales smooth, head ver}^ distinct from neck JSormonofus. 



Scales keeled, vertebrals bioarinate ; anterior teeth not enlarged. GonionotopJiis. 

 Scales keeled, vertebrals bicarinate ; anterior teeth strongly 



enlarged Simocephalus. 



4. Papil round; two superposed anterior temporals, or, if anterior temporal 



single, 3 upper labials entering the ej^e, or ventrals more than 165. 

 a. Scales not oblique, in 31 rows ; ventrals 245-254 ... Zamenis. 

 h. Scales more or less oblique, at least on the anterior part of the body, in 

 13 to 19 rows ; body usually very slender (Tree-Snakes). 



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

 as dorsals. 



* Scales smooth. 



Sabcaudal shields not keeled ChloropJiis. 



Subcaudal shields keeled on each side and with a notch corres- 

 ponding to the keel, same as on the ventrals FhUothamnns. 



**• Scales keeled. 

 Subcaudal shields keeled and notched on each side ; a single 



anterior temporal Gastropi/xis. 



Subcaudal shields not keeled ; usually two superposed anterior 



temporals Sapsidojph rijs . 



j3. Scales in 13 or 15 rows, verj'- oblique, laterals 



shorter than dorsals ; eye very large Thrasops. 



y. Scales in 17 or 19 rows, very oblique ; ej-e very 



large Wiamnophis. 



c. Scales not oblique, in 15 to 21 rows. 

 A single anterior temporal ; ventrals 171-224 ; rostral not twice 



as broad as deep Coronella. 



Two superposed anterior temporals ; ventrals 125-168 Grayia. 



B. Rostral veiy large, with angular horizontal edge. 



Eye in contact with labials ; scales in 15 rows 'Prosymna. 



Suboculars separate the eye from the labials ; scales in 19 to 25 



rows Scaphiopltis. 



II. No loreal, nasal in contact with praiocular. 



Eye small, with round pupil ; no internasals, prasfronlal single ; 



scales smooth, iu 15 rows FoecilopJiolis. 



Ej^e moderate or rather large, with vertical pupil ; a pair of 

 internasals and a pair of prsefrontals ; scales strongly keeled, 

 in 20 to 27 rows Dasypelfis. 



1. Tropidonotus. 



Kuhl, Bull. Sc. Nat. ii. 1824. p. 81 ; Bonleng. Cat. Sn. iii. 

 p. 192. 



Si/nojjsls of the Sfecies. 



I. Scales smooth ; two upper labials entering the eye. 



Scales in 17 rows ; ventrals 117-135 ; anal usually entire : sub- 



caudals 75-95 T.fuliginoides. 



Scales in 15 rows; ventrals 125-143; anal divided; subcaudals 



68-77 T. variegatus. 



Scales in 19 rows ; ventrals 131-150 ; anal divided; subcaudals 



55-95 T. oUvaceus. 



II. Scales strongly keeled, in 21-27 rows; suboculars separate 



the eye from the labials T.ferox. 



Proc. ZooL. Soc— 1919,'No. XX. 20 



