Acanth odd ctyliis. 



69 



Measurements (in millimetres) : 



From end of snout to vent ' . 

 ,, ,, )i fore limb . 



Length of head .... 

 Width of head .... 

 Depth of head .... 



Fore limb 



Hind limb .... 



Foot 



Tail 



1. o^, Mettamer, Tunisia. 2. ?, Duirat, Tunisia. 3. (J, El 

 Kreider, Orau. 4. $ , Mecheria, Oran. 



Var. LATASTII, Bouleuger. 

 Lataste has proposed to separate the examples from Southern 

 Tunisia and the Algerian Sahara as a var. deserti* from the Egyptians, 

 his var. aaviijnijl, with the following definition: — 



Taille grande et forme t'lanci'e. Ecailles dorsales pen rcgulieres et 

 vaguement carcnces. Coloration assez intense et plus ou moins pom- 



mek'e var. savujnyi. 



Taille petite et forme grcle. Ecailles dorsales regulicrement rhom- 

 boidales et nettement carenees. Coloration plus ou moins effact'e. 



var. deserti. 



This definition leaves out of consideration too many exceptions to 

 be of much use. Thus the following table shows the lizards from 

 Biskra to be as large as those from Egypt ; the keels on the scales are 

 more often absent or indistinct than decidedly marked, t and some of 

 the specimens from the Plateaux of Algeria, t which were included 

 under the var. deserti, are as vividly coloured and marked in precisely 

 the same fashion as the Egyptians. It is, in fact, almost impossible 

 to distinguish some of the Tunisian and Algerian specimens from the 

 typical form, 1)ut they are linked by close gradation with the better- 

 defined desert lizards, e:;treme specimens of which, in the shape of the 



* This name cannot be used in this sense, as Milne-Edwards's Lacerta deserti 

 is not Lepechin's, and is, besides, based on specimens from Olivier's collection 

 from the " Empire Ottoman," probably Syria. 



t Lataste had probably in mind the specimens now refm-red by me to the var. 

 maculatus. 



t Wed Dermel, Wed Sedeur; also the type of Zootoca deserti, Gthr., from 

 Ngoussa, south of the Mzab. 



