NUMBERS AND DISTRIBUTION. 



215 



Genus CAUSUS. 



Two Species in South Africa. 

 KEY TO THE SPECIES. 



Snout obtuse, more or less prominent ; vcntrals 

 120-155. Poison glands considerably elon- 

 gated 



Snout pointed, prominent, more or less turned up 

 at the end ; ventrals 113-125 .. 



Causus rhombeatus. 

 Caustis defillippii. 



Fig. 86. — The venomous Hornsman or Honied .-Vcldcr (Bilis cornuta) of the sandy 

 inland parts of South Africa. Tliere arc two species. The chief difference is 

 that the one known as Bitis cornuta has several small, erect horn-like scales 

 over the eyes, while the other (Bitis caudalis) has only one erect horn-like scale. 



I. Causus rhombeatus. Night or Demon Adder ; Nacht Adder. 



Synonyms — Sepedon rhombeatus ; Distichunts maculatus ; Aspidelaps 

 rhombeatus. 



Colour — Olive or pale brown above, rarely uniform, usually with a 

 dorsal series of large rhomboidal or V-shaped dark brown spots 

 which may be edged with whitish ; usually a large dark j\-shapcd 

 marking on the back of the head, the point on the frontal, and 



