82 THE SNAKES OF SOUTH AFRICA. 



7. Genus Prosymna. — Scales smooth, in 15 or 17 rows. Pupil vertically 



elliptic ; rostral very large, with angular horizontal edge ; pos- 

 terior maxillary teeth strongly enlarged. Maxillary bone short 

 with 7 or 8 teeth. 



8. Genus Homalosoma. — Scales smooth in 15 rows. Pupil round ; 



rostral small ; nasal single ; anterior maxillary teeth longest. 

 Maxillary short, with 10 to 12 teeth. Tail short, sub-caudals in 

 two rows. 



9. Genus Chlorophis.— Scales smooth with apical pits in 15 rows. 



Tail long (sub-caudals more than 80 pairs) ; pupil round ; posterior 

 maxillary teeth longest. Sub-caudals not keeled, and in 2 rows. 



10. Genus Philothamnus. — Scales smooth with apical pits, in 13 or 15 



rows, disposed obliquely, at least on the anterior part of the body. 

 Sub-caudals keeled and notched, like the ventrals. Tail long. 



11. Genus Simocephalus. — Scales keeled, without pits, in 15 or 17 rows ; 



those of the vertebral row enlarged and bi-carinate ; anterior 

 maxillary teeth longest. Pupil vertically elhptic. 



12. Genus Dasypeltis. — Scales in 23 to 27 rows, laterals very obUque, 



and with serrated keels ; teeth very small and few. Pupil 

 vertically elliptic. 



Genus TROPIDONOTUS. 



Two Species in South Africa. 



KEY TO THE SPECIES. 



Ventrals 162-180 ; anal entire. Scales smooth Tropidonotus IcBvissimus . 

 "Ventrals 1 31-149 ; anal divided. A single an- 

 terior temporal . . . . . . . . Tropidonotus olivaceous. 



1. Tropidonotus l^vissimus. Watermeyer's Black Snake. 

 Synonyms — Natrix lavissimus ; Grayia lubrica. 



Colour — Dark shining black above, a narrow yellow line on either side 

 of the head behind the eye ; below, yellow, with a narrow ill- 

 defined dark line running the whole length of the body along 

 the centre of the ventrals. The two outer rows of scales spotted 

 and blotched with black. 



Average length — 3 feet. 



Distribution — Eastern Province, Cape Colony ; Natal. 



2. Tropidonotus olivaceous. Banded Olive Snake ; Olyfen Slang. 

 Synonym — Coronella olivacea. 



Colour — Olive or brown above, with a more or less distinct darker 

 vertebral band 4 or 5 scales wide, bordered on each side by a 

 series of whitish dots ; flanks and ends of ventrals olive ; upper 

 lip yellowish, the sutures between the shields black ; ventrals 

 yellowish, sometimes edged with olive. 



Average length — 2 feet. 



Distribution — Southern Rhodesia ; North to Tropical Africa. 



Genus ABLABOPHIS. 

 One Species in South Africa. 



Scales smooth with apical pits, in 19 rows. 

 Frontal at least once and a half as long as 

 broad ; maxillary teeth equal . . . . . . A blabophis rufulus. 



