On a neio Wuitty (y Acaulhodaclylu.s boskiunus. .">!'.• 



LVIII. — On a new Variety 0/ Acanthodactylus boskiatius, 

 Baud., from the Euphrates. By G. A. Boulenoer, F.R.S. 



(Published by pennission of tlie Trustees of the British Museum.) 



I AM indebted to my son, Capt. C. Ij, Bouleiijjcr, for examples 

 of a lizard, referable to Acanthodacti/lus buskianus, cauglit 

 by himself and Capt. Harrison at Ramadieh on the Eni)lirate8 

 front in 1918, that are of special interest not only as 

 extending the known range of a widely distribnted species 

 (Syria, Arabia, North Africa, and the Soudan ), but as dilfer- 

 ing from all other specimens, of which 1 have examined 

 about two hundred, by a character to which a great 

 importance was formerly attached in distinguishing the 

 species of Acanthodactylus and Eremias : in 7 out of the 8 

 specimens collected, the subocular borders the month instead 

 of its lower edge forming an angle wedged in between the 

 fourth and fifth or fifth and sixth upper labials ; otherwise 

 they agree with the typical form, the Lacerta boskiuna of 

 Daudin, in the number of scales (38 to 43 across middle of 

 body, l^ or 16 between hind limbs) and of femoral pores 

 (23 to 27 on each side *). The scales round the base of the 

 tail are more numerous (23 to 27 in the fourth or fifth 

 whorl, instead of 18 to 22). The first supraocular shield is 

 divided into 2 or 3 parts, and in four of the specimens there is 

 an agygos shield between the prefrontals. There is nothing 

 8])ecial to note concerning the coloration, except the absence 

 of a light vertebral streak ; the young has 4 white streaks on 

 the upper surface of the body, 6 on the nape, and one on 

 each side, separated by broader black streaks, each of which 

 may bear a series of round white spots. 



The largest male measures 81 mm. from snout to vent, 

 the largest female 80. 



The condition of the subocular shield points to this form, 

 which I propose to call vur. enj/hralicus, Ijeing the nearest to 

 the hypothetical primitive Acanthodactylus, according to the 

 views expressed by me in recent papers dealing with the 

 evolution of the Laccrtidie. The three forms into whieh 

 A. boskianus may be divided, although not sharply definable, 

 constitute a highly suggestive gradational series : — 



]. Var. eujihraticus (Euphrates). Subocular usually bor- 

 dering the mouth ; 38 to 43 scales across middle of body, 



♦ In one of the males there are 2-3 additional pores, fonuiug a second 

 series behind the other nt the distal end of tla- thigh, 



Ann. (fc Mag. N. Hist. Scr. 9. Vul. iii. 3») 



