Acanfhodactyhcs. 



71 



1. (^, Biskra. 2. $, Biskra. 3. (5^, Wargla. 4. $ , Wargla-El 

 Grolea. 



Habitat. — Tripoli, Southern Tunisia, Algeria in desert tracts on the 

 high plateaux and far into the Sahara. 



Yar. SPINICAUDA, Doumergue. 



This is the most distinct of the varieties of A. jmrdalis. 



Head about 1 ^ times as long as broad ; snout a little longer than 

 the postocular part of the head ; snout more pointed, nasals more 

 swollen, with the lanceolate concavity very shallow, sometimes hardly 

 distinct. Hind liml) longer, reaching the ear in males, the collar in 

 females ; foot IJ to l-J- times the length of the head ; fourth toe at 

 least a trifle longer than the head, up to IJ. Tail 1| to 1| times as 

 long as head and body, much flattened at the base, especially in males. 



First supraocular nearly always entire ; one or two series of granules 

 })etween the supraoculars and the superciliaries ; subocular wedged in 

 between the fourth and fifth upper labials, narrowly bordering the 

 mouth in one specimen ; a strong auricular denticulation, formed of 

 4 or 5 obtusely pointed lobules. 



26 to 31 gular scales in a straight line ; no gular fold ; collar 

 attached in the middle, composed of 9 to 12 plates. 



Scales rather strongly keeled, at least on the posterior two-thirds of 

 the back, 44 to 56 across the middle of the body. Ventral plates, all 

 except the outermost broader than long, in 12 longitudinal series, in 

 27 to 29 sti'aight transverse series in males, 31 to 33 in females. 



17 to 24 femoral pores on each side. Denticulation a little more 

 developed on the outer side of the fourth toe than on the inner ; 20 to 

 22 tricarinate lamellae under the fourth toe. 



Upper caudal scales strongly keeled, those on the sides just behind 

 the vent with the keels strongly raised, especially in the males, forming 

 very prominent rounded or pointed tubercles, producing a serrated 

 outline on the base of the tail. 



Grey or pale buff above, with longitudinal series of yellowish or 



