30. UROCENTRON. 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 inferiorly, 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. 
millim. millim: 
Total length........ 124 Fore limb ...... 39 
Head -c5 sx oeaeaeds 20 Hind limb ...... 49 
Width of head...... 17 ft) eee ee 46 
BOY i acvatone ine scatee 58 
Guianas ; Brazil. 
a Q. Brazil. 
bg. British Guiana. 
c, d,ef. SQ. S. America. 
2. Urocentron flaviceps. 
Doryphorus azureus, var., A. Dum. Cat. Méth. Rept. p. 85. Be 
flaviceps, Guichen. in Casteln. Am. Mér., Rept. p. 26, pl. ili. 
fig. 2; A. Dum. Arch. Mus, viii. p. 560. 
Uranocentrum flaviceps, O’Shaughn. Proc. Zool. Soc. 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 groenish- 
white or pale olive; upper surface of head sometimes yellowish. 
millim. : millim 
Total length........ 168 Fore limb ..... 53 
Head: (as aveagtete ons 28 Hind limb .... . 68 
Width of head...... 21 STRAND: scesspeie ts aeteie ak cares 62 
Body occ seegeegers 7 
Upper Amazons. 
