30. UROCENXKON. 183 



Snout short, broadly rounded, lips somewhat swollen ; nostril 

 turned upwards ; upper head-scales small, with small granular 

 asperities ; a series of slightly dilated transverse supraoculars ; occi- 

 pital a little longer than broad, narrower than the supraocular 

 region ; five or six upper and six or seven lower labials ; ear- 

 opening moderate, its anterior border without denticulation. Sides 

 of neck irregularly plicate ; a strong transverse gular fold, and a 

 second, less regular, in front. Lateral and anterior dorsal scales 

 very small, granular, smooth ; posterior dorsal scales larger, sub- 

 rhomboidal, obtusely keeled ; ventrals larger, squarish, imbricate, 

 smooth. Digits slender. The adpressed hind limb reaches the 

 shoulder or slightly beyond. Tail shorter and narrower than the 

 body, flat interiorly, about twice as broad as deep, with whorls of 

 very large, obtusely keeled spinose scales, the spines strongest on the 

 sides. Azure blue or olive above, with crescentic black cross bands ; 

 lower surfaces greenish or yellowish. 



milliui. millim. 



Total length 124 Fore limb 39 



Head 20 Hind limb 49 



Width of head 17 Tail 46 



Body 58 



Guianas : Brazil. 



a. 



2 . Brazil. 



b. 5 • British Guiana. 



c, d, e-f. J 2 . S. America. 



2. Urocentron flaviceps. 



Doryphorus azureus, var., A. Dum. Cat. Mctli. Repl. p. 85. 



flaviceps, Guivhen. in Casteln. Am. Mer., Rept. p. 20, pi, iii. 



flg. 2 ; A. Dum. Arch. Mus. viii. p. 5G0. 

 Uranocentrum flaviceps, O^Shaug/m. Proc. Zool. Sue. 1881, p. 245. 



Upper head-scales very convex. Dorsal scales small, rhomboidal, 

 imbricate, strongly keeled, increasing in size posteriorly ; lateral 

 scales smaller ; ventrals as large as dorsals, feebly keeled. Tail 

 quite flat, nearly as broad as the body, lanceolate ; caudal scales 

 large, rhomboidal, forming longitudinal and transverse series, 

 strongly keeled, spinose, the spines strongest on the sides. Other- 

 wise as in the preceding species. Black, uniform (males) or with 

 numerous round greenish spots and the lower surfaces greenish- 

 white or pale olive : upper surface of head sometimes yellowish. 



miUiin. milliru. 



Total length 108 Fore limb 53 



Head 2^ Hind limb 08 



Width of liead 21 Tail 02 



Body 78 



Upper Amazons. 



