296 mr. g. a. boulenger on the 



2. Causus lichtensteinii. 



Aspidelaps lichtensteinii Jan, Rev. et Mag. Zool. 1859, p. 511.. 



Causus lichtensteinii Bouleng. t. c. p. 470. 



From the Gold Coast and Uganda to the Congo. 



2. BiTis. 

 Gray, Zool. Miscell. p. 69 ; Bouleng. Cat. Sn. iii. p. 492. 



Syno2)sis of the Species. 



One or two series of scales between the nasal and the rostral; 8 to 



11 scales across the head, from eye to eye B. arietans. 



4 or 5 series of scales between the nasal and the rostral; 13 to 16 

 scales across the head, from eye to eye ; a single enlarged, some- 

 times honi-like scale above the internasal, in contact with its 

 fellow B.gahoniccu 



4 to 6 series of scales between the nasal and the rostral; 14 to 16 

 scales across the head, from eye to eye ; 2 or 3 enlarged, horn- 

 like scales above the internasal, usually with small scales 

 between them B.nasicornis. 



1. BiTIS ARIETANS. 



Vipera arietans Merr. Tent. p. 152. 

 Bitis arietans Bonleng. t. c. p. 493. 



Tropical and iSoutli Africa, northwards to S. Morocco ; Southern 

 Arabia. 



2. BiTIS GABONICA. 



Echidna gahonica Dum. & Bibr. Erp. Gen. vii. p. 1428,. 

 pi. Ixxx. b. 



Bitis gabonica Bouleng. t. c. p. 499. 



Tropical Africa. 



3. Bitis nasicornis. 



Coluber nasicornis Shaw, Nat. MiscelL iii. pi. xciv. 

 Bitis nasicornis Bouleng. t. c. p. 500. 

 Ti"opical Afiica. 



3. Cerastes. 



Wagl. Syst. Amph. p. 178 ; Bouleng. Cat. Sn. iii. p. 501. 



1. Cerastes cornutus Forsk. Descr. Anim. p. ix; Bouleng. 

 t. c. p. 502. 



Borders of the Sahara and Soudan ; Arabia and Palestine. 



4. EcHis. 

 Merr. Tent. p. 149 ; Bouleng. Cat. Sn. iii. p. 504. 



1. ECHIS carinatus. 



Pseudoboa carinata Schneid. Hist. Amph. ii. p. 285. 

 Uchis carinatits Bouleng. t. c. p. 505. 



Desert and sandy distiicts of Africa north of tlie Equator;. 

 Southern Asia from Transcaspia and Arabia to India. 



