422 Dr. J. Anderson on the Presence of 



the right side, whilst the supranasal of the opposite side is 

 excluded from the rostral by a small scale. In the other viper 

 from the Emerald Mines both supranasals touch the rostral, 

 but in the two individuals from that locality the supranasals 

 in each case are separated in the mesial line by a single scale. 



The downward projection of the supranasals in these 

 examples of E. coloratus, feeble though it be, is a variation in 

 the direction of E. carinatus, in which these shields are 

 markedly developed, broadly in contact with each other in 

 the mesial line and in a varying degree with the rostral. In 

 a specimen of E. coloratus from the Dead Sea the supranasals 

 are large and directly in contact with the rostral, but in 

 another from the same locality they are excluded by the infra- 

 nasals. In both of these vipers the nasals are separated from 

 the rostral by infranasals. The same variation occurs in 

 vipers from the Hadramut, but, as in E. carinatus^ the supra- 

 nasals are in contact mesially. In a specimen in the British 

 Museum said to be from Socotra the rostral is rounded like 

 the type and the supranasals are excluded from contact with 

 it by the infranasals, of which there are two, the second 

 resting on the first upper labial. 



The essential feature of E. coloratus is the broad separation 

 of the nasal shields from the rostral and from the first upper 

 labial, whereas in E. carinatus the nasals rest directly on the 

 rostral and first upper labial. The accompanying figures 

 (c and d) represent the front view of the snout of E. carinatus 

 from Sind and from Jebba on the Upper Niger respectively ; 

 and if they are compared with the two modifications of E. colo- 

 ratus (figs, a and b) the differences between the two species 

 become apparent. 



d. 



Echis carinatus. 



As the scales around and between the eyes in the two 

 species vary very nearly within the same limits as to 

 numbers, they are practically by themselves of little use as 

 guides to the distinction of the species ; and the same may 

 be said of the scales between the eyes and upper labials, as 



