AND BATHACHIAXS OF BAKBAET. 155 



1. Cerastes vipeea, Linnajus, 1766. (Plate XVIII. fig. 2.) 

 Vipera avicennee, Strauch. 



Snout very short, rounded ; eye very small. Head-scales small, tubercularly keeled ; 

 nostril between two small shields ; no horn-like scales over the eye ; three or four 

 series of keeled scales between the eye and the labials. Scales in 23 to 25 rows. A 

 strong keel on each side of the ventrals. Yellowish brown, sand-colour above, with or 

 without darker spots ; lower parts white. 



Total length 240 millim., tail 30. 



This small Viper inhabits the desert of Algeria, Tunisia, Tripoli, and Egypt. It was 

 first recorded in Algeria from the Western Desert by Dumeril and Bibron {Echidna 

 atricauda), and M. Lataste collected specimens at Bou-Saada, Biskra, and between Bou- 

 Saada and Biskra. M. Lataste did not come across it in Tunisia, but was informed that 

 Marquis Doria possesses several specimens from the southern parts. 



The specimen figured by Jan under the name of Vipera avicennm is a Cerastes cornutus 

 without horns. As there exists no figure of this viper, I have supplied one on 

 Plate XVIII. fig. 2. 



O' 



2. Cerastes coknutcs, Forskal, 1775. 

 Vipera cerastes, Sclilegel, Gervais, Strauch. 



Snout very short and broad ; eye rather small, usually with a large, ribbed, horn-like 

 scale above. Head-scales small, tubercularly keeled ; nostril in a single small nasal ; 

 four or five series of keeled scales between the eye and the labials. Scales in 29 to 33 

 rows. An obtuse keel on each side of the ventrals. Yellowish-brown sand-colour 

 above, with or without brown spots forming regular longitudinal series, white below. 



Total length 630 millim., tail 75. 



Inhabits the Sahara, extending eastwards to Arabia. Schlegel records it from Biskra, 

 Strauch from Djelfa, Laghouat, Saida, Biskra, and Batna, and Boettger from Geryville. 

 M. Lataste obtained it in Algeria, at Bou-Saada and at Bordj-Tayer-Easson, and in 

 other localities in the sandy Sahara, and at Wed Magra, in the southern parts of the 

 High Plateaux ; he found it common throughout Southern Tunisia. 



Figures: Jan, Icon. Ophid. livr. 45, pi. v. {Vipera cerastes and V. avicennce), ?jiA 

 Geoffroy, Descr. de I'Egypte, Eept. pi. vi. fig. 3. 



3. EcHis, Merrem, 1820. 



Upper surface of head covered with scales. Scales keeled, in 25 to 35 rows, the 

 laterals disposed obliquely. Subcaudals in a single row. 

 A single species in Barbary. 



I. EcHis CAEiNATA, Schneider, 1801. 



Snout very short and rounded. Nostril between three shields, the anterior and upper 



