28. TTEOMASTIX. 405 



28. UEOMASTIX. 



Uromastix, Merrem, Tent. Syst. Amph. p. 56 ; Fitzing. N. Classif. 

 Rept. p. 17; Wayl. Syst. Amph. p. 145; Wiegm. Herp. Mex. 

 p. 17 ; Dum. S; Bibr. iv. p. 533 ; Fitzing. Syst. Rept. p. 86 ; Gray, 

 Cat. p. 261 ; Giinth. Rept. Brit. Ind. p. 155, and Phil. Trans. 



Mastigura, Flem. Phil. Zool. ii. p. 277. 



Oentrocercus, Fitaing. Syst. Rept p. 85. 



Saara, Gh'ay, Cat. p. 85. 



Oentrotraclielus, Strauch, Bull. Ac. St. PStei-sb. vi. 1863, p. 479. 



Tympanum distinct. Incisors large, uniting in the adult into one 

 or two cutting-teeth, separated from the molars by a toothless 

 interspace. Body depressed, without crest. No gular pouch ; a 

 transverse gular fold. Tail short, depressed, covered with whorls of 

 large spinose scales. Prseanal and femoral pores present. 



Arid tracts of North Africa and Southern Asia. 



The species resembling one another so much in general structure, 

 the following description will suffice for all ;- - 



Head small, feebly depressed, with short snout and obtuse 

 canthus rostralis ; nostril large, directed backwards, nearer the end 

 of the snout than the eye ; tympanum large, vertically elliptic ; 

 upper head-scales smooth, much larger than those on the body, 

 smallest on supraorbital region ; occipital not enlarged ; labials 

 small and numerous. Neck strongly plicate. Limbs short and 

 thick; hind limb with spinose conical tubercles; digits short and armed 

 with strong claws. Scales on upper surface of body very small, on 

 belly larger, flat, smooth, juxtaposed or subimbricate. 



Synopsis of the Species. 



I. The whorls of spinose scales on the upper surface of the tail 



not separated by small scales. 



A. The caudal scales form regular 



annuli, those on the lower surface 

 being as long as those on the 

 upper 1. oriiatus, p. 406. 



B. Two or more transverse rows of scales on the lower surface of 



the tail correspond to one ou the upper. 



Scales larger (about 90 from the gular fold 



to the prseanal pores) ; no enlarged scales 



on the flanks 2. acanthinurus, p. 406. 



Scales on the body very minute ; flanks with 



scattered slightly enlarged scales 3. spinipes, p. 407. 



Scales very minute ; no enlarged ones on 



the flanks 4. mlcrolepis, p. 407. 



II. The whorls of spinose scales on the upper surface of the tail 



separated by small scales. 



Caudal spines small, the lateral ones largest ; 

 no strongly enlarged tubercles- on the 



