2l6 



THE SNAKES OF SOUTH AFRICA. 



an oblique dark streak behind the eye ; labials usually dark- 

 edged ; lower parts yellowish white or grey, uniform, or the 

 shields edged with black. 



Average length — 2 feet. 



Distribution — -All over South Africa ; North to Tropical Africa. 



Causus defiii.ippii. Snouted Night Adder ; Snoet Nacht Adder. (Gesnoet 

 Nacht Adder.) 



Synonyms — Heterodon defillippii ; Causus rostratus. 



Colour — Grey or brown above, vertebral region darker, with a series 

 of large rhomboidal or V-shaped dark brown spots ; a large 

 A-shaped dark brown marking on the occiput, the point on the 

 frontal ; an oblique dark streak behind the eye ; upper labials 

 dark edged ; yellowish white beneath, uniform, or with small 

 greyish-brown spots. 



Average length — i foot 6 inches. 



Distribution — Griqualand ; Natal ; Zululand ; Transvaal ; Southern 

 Rhodesia ; East and Central Africa. 



:^^'i: 



Fig. 87. — The poisonous Night or Demon Adder (Causus thomhcatus). 

 Note the characteristic triangular blackish mark on its head. 



Genus BITIS. 

 Six Species in South Africa. 

 KEY TO THE SPECIES. 

 Nostrils directed upwards ; scales in 31 to 41 rows . . 

 Nostrils directed upwards and outwards ; scales in 21 

 to 31 rows. Supraocular region not raised, with- 

 out horn-like scales ; sub-caudals well developed 

 and smooth in both sexes. Outer row of scales 

 smooth . . .... 



Same as the former except that outer row of scales are 



keeled . . .... 



Supraocular region raised, without horn-Hke scales ; 



sub-caudals well developed and smooth in both 



sexes . , 



Bitis arietans. 



Bitis peringueyi. 

 Bitis atropos. 



Bitis inornata. 



