29 



having their dorsal scales a little more strongly keeled. In both 

 there are seven prseanal pores. 



The females from the Hadraaiut have distinct prieanal pores, 

 and also those from Suez and Heluan (see Table). 



The specimens of this species from Lower Egypt also illustrate 

 its variations. I have met with it on the plain of Suez and in the 

 desert (Wadi Hoaf) at Heluan. The lizard from the former 

 locality has its dorsal scales practically smooth, whereas those 

 from the latter have distinctly keeled scales. The specimens 

 in the British Museum referred to A. arenaria, Heyden, and 

 also from Egypt, exactly resemble the lizard from the plain 

 of Suez, whereas two specimens in the British Museum from 

 Mount Sinai, and referred to A. sinaita, Heyden, correspond to 

 one of my Heluan lizards, a young individual. 



The adult female from Heluan (Wadi Hoaf) has the mesial 

 line of dorsal scales very slightly, if at all, enlarged, considering 

 the fact that in all specimens belonging to one or other of 

 these varieties the scales gradually diminish in size towards 

 the sides. In this specimen, however, the scales are decidedly 

 imbricate and distinctly keeled. On the other baud, in the spe- 

 cimen from the plain of Suez the scales are only feebly imbricate, 

 and carination is aU but completely lost. The mesial dorsal 

 scales hold almost the same proportions to the lateral scales as 

 in the Wadi Hoaf female. In both of these specimens, and in 

 the Hadramut examples as well, the ventrals do not vary in size; 

 the slight dilference between them is confined to the varying 

 development of the dorsal scales. As a rule, the Hadramut 

 specimens have the mesial dorsal scales decidedly larger than the 

 ventrals, and all have distinctly keeled scales, but, among some 

 of them, the difference in size between dorsals, laterals, and 

 ventrals graduates in the same way as in the Wadi Hoaf female. 

 In view of these facts, and the exact similarity of these 

 lizards in the other details of their external structure, the dif- 

 ferences I have pointed out can only be regarded as illustrative 

 of variation, but they present no stability to entitle them to 

 varietal rank. It is only another example of the remarkable 

 modifications to which the scales of many species of the genus 

 Agama are subject, and which is perhaps most strongly pro- 

 nounced in that strangely variable form A. inermis, Eeuss, 

 which in one of its phases could never be recognized under this 

 specific term. 



