On a new Variety of Acauthodactylus boskianus. 549 
LVIII.—On a new Variety of Acanthodactylus boskianus, 
Daud., from the Euphrates. By G. A. Boutencer, F.R.S. 
(Published by permission of the Trustees of the British Museum.) 
I am indebted to my son, Capt. C. L. Boulenger, for examples 
of a lizard, referable to Acanthodactylus boskianus, caught 
by himself and Capt. Harrison at Ramadieh on the Euphrates 
front in 1918, that are of special interest not only as 
extending the known range of a widely distributed species 
(Syria, Arabia, North Africa, and the Soudan), but as differ- 
ing from all other specimens, of which I have examined 
about two hundred, by a character to which a great 
importance was formerly attached in distinguishing the 
species of Acanthodactylus and Evemias: in 7 out of the 8 
specimens collected, the subocular borders the mouth 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 boskiana of 
Daudin, in the number of scales (38 to 43 across middle of 
body, 14 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 
special 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 var. euphraticus, being the nearest to 
the hypothetical primitive Acanthodactylus, according to the 
views expressed by me in recent papers dealing with the 
evolution of the Lacertide. The three forms into which 
A. boskianus may be divided, although not sharply definable, 
constitute a highly suggestive gradational series :— 
1. Var. euphraticus (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, forming a second 
series behind the other at the distal end of the thigh. 
Ann. & Mag. N. Hist. Ser. 9. Vol. iii. 36 
