76 VENOMS 
two small shields, separated from their neighbours by 5—6 series 
of scales ; 10—12 supralabials ; 3 infralabials. Scales on the body 
in 23—27 rows; 102—122 ventrals, rather strongly keeled at the 
sides ; 18—26 subcaudals. Colour dull yellow, pale brown or red- 
dish, with or without black spots; end of tail often black above ; 
ventral surface white. 
Total length, 340 millimetres ; tail 30. 
Habitat: Northern border of the Sahara, from Algeria to Egypt. 
The snakes belonging to this genus live constantly hidden in the 
sand, lying in wait for small birds, which alight beside them with- 
out suspicion, mistaking their horns for insects or larvæ ; they also 
feed upon mice. Their poison-fangs are of relatively large size. 
These small and exceedingly active vipers, whose colour har- 
monises marvellously with their surroundings, are very dangerous 
to the Arabs and blacks, who walk barefooted; they frequently 
cause fatal accidents. 
They are able to exist for a very long time without drinking. 
They are attracted by the fires which are lighted at night round 
caravan encampments. 
(e) Echis. 
(See Asia, p. 48.) 
(1) H. carinatus (Efa, Viper of the Pyramids).—The same as 
met with in Persia, Arabia, and India. Very common in the 
environs of Cairo, and throughout Egypt and Abyssinia. It often 
makes its way into towns and villages. Brehm records that he 
more than once found an H/fa in his house at Khartoum, and that 
on one occasion he discovered one of these vipers coiled up beneath 
the covering of his bed. At another time, getting up in the night, 
he put his foot on one of these animals and was not bitten, the 
reptile being very fortunately just at that moment in the act of 
devouring a tame bird which it had seized. 
it hardly ever happens that a native of Egypt can bring 
