Acanthodactylus. 63 



The six forms here defined are not always easy to distinguish, 

 owing to intergradation. The following synopsis will help in their 

 identification. 



I. Scales in middle of body smooth or feebly keeled : if strongly keeled, convex ; 



tail of young red. 



Subocular not reaching the oral border, or entering it veiy 

 narrowly ; suture between the nasals ^ to i the length of 

 the frontonasal . . . . . Forma typica. 



Subocular largely bordering the mouth ; suture between the 

 nasals rarely more than I the length of the frontonasal 



Var. belli, Gray. 



Subocular separated from the oral border by a small shield 

 detached from it ; suture between the internasals i the 

 length of the frontonasal . . Var. atlanticus, BIgr. 



II. Scales in middle of body flat, with strong, well-defined keels. 



Subocular bordering the mouth ; tail red in the young 



Var. mauritanicus, Doum. 



Subocular usually not reaching the mouth ; prefrontals in 

 contact with each other; tail blue in the young . Var. Hand, Doum. 



Subocular usually not reaching the mouth ; prefrontals often 

 separated by one or two shields ; frontonasal often divided 

 into two ; tail red in the young . . . Var. lineomaculatus, D & B. 



2. ACANTHODACTYLUS TEISTEAMI. 



.'' Scapteira leiocerca, G-ray, Ann. N. H. i, 1838, p. 281. 



Zootoca tristrami, Griinth. Proc. Zool. Soc. 1864, p. 491 ; Tristram, 

 Faun. Palest, pi. xvi, fig. 2 (1884). 



Acanthodactylus dorsalis, Peters, Mon. Berl. Ac. 1869, p. 62. 



Acanthodactylus tristrami, Bouleng. Proc. Zool. Soc. 1881, p. 746, 

 pi. Ixiv, fig. 1 ; Lataste, Ann. Mus. Geneva (2) ii, 1886, p. 482 ; 

 Bouleng. Cat. Liz. iii, p. 68 (1887), and Bull. Soc. Zool. Prance, 1918, 

 p. 147. 



Lacerta platyura, Hempr. & Ehrenb. Symb. Phys., Zool., Amph. 

 pi. ii, fig. 3 (1899). 



Habit robust, body depressed. Head about 1| to 1^ times as long 

 as broad, its length 4 to 4-|- times in length to vent, its depth equal to 

 the distance between the anterior corner or the centre of the eye and 

 the tympanum ; a rather feeble concavity between the prefrontals and 

 along the anterior half of the frontal ; snout obtusely pointed, with 

 obtuse canthus and feebly concave loreal region ; nasals not or but 

 very feebly swollen. Pileus If to 2 times as long as broad. Neck as 

 broad as the head or a little broader. The hind limb reaches the axil 

 or the shoulder in males as in females ; foot 1| to l-i- times as long as 



