174 IGTTANID^, 



supraoculars not measuring more than half the width of the supra- 

 ocular region ; occipital much broader than the latter, nearly twice 

 as broad as long. A short curved fold above each shoulder, not 

 descending on the chest ; an oblique fold or pouch on each side of 

 the neck connected with its fellow by a transverse gular fold. A 

 vertebral denticulation. Dorsal scales moderate, rhomboidal, strongly 

 keeled, the keels forming slightly oblique lines ; lateral and ventral 

 scales a little smaller, latter smooth. Limbs rather short. Tail a 

 little longer than head and body, roundish. Olive above, variegated 

 with dark yellow ; lower surfaces yellowish white. 



From snout to vent 60 millim. ; tail 81 millim. 



Peru. 



5. Tropidurus peruvianus. 



Microlophus peruvianus, Gray^ Cat. p. 221. 

 Lopbyrus araucauus, Lesson, Voy. Coqtiille, Rept. pi. ii. fig. 1. 

 Stellio peruvianus, Less, I. c. fig. 2. 

 Tropidurus microlophus, Wiegm. Nova Acta Ac. Leojy.-Carol. xvii. 



1835, i. p. 223, pi. xvi. 



heterolepis, Wiegm. I. c. p. 225, pi. xvii. fig. 1. 



Microlophus lessonii, Ditm. of Bibr. iv. p. 336; Guichen. in Gay, 



Hist. Chile,^ Rept. p. 48. 

 Steirolepis microlophus, Fitzing. Syst. Rept. p. 72. 



heterolepis, Fitzing. I. c. 



peruviana, Fitzing. I. c. p. 73. 



xanthostigma, Tschucli, Fawn. Per., Herp. p. 29. 



tigris, Tschiidi, I. c. p. 30. 



thoracica, Tschudi, I. c. p. 31. 



quadi'ivittata, Tschudi, I. c. p. 32. 



Microlophus peruvianus, Girard, U.S. Explor. Exped., Herp. p. 314; 



CojK', Journ. Ac. PMlad. (2) viii. 1876, p. 173. 



heterolepis, Cope, I. c. p. 171. 



iuguinalis, Cope, I. c. p. 172. 



Upper head-scales smooth ; a series of four to six more or less 

 transversely enlarged supraoculars ; occipital usually as long as broad 

 or a little broader than long, nearly as broad as the supraocular 

 region ; ear-opening with a fringe of short pointed scales ; temples 

 granulate. A strong curved antehumeral fold, nearly meeting its 

 fellow on the throat ; latter with more or less distinct cross folds ; 

 sides of neck minutely granulate, strongly plicate. Body more or 

 less depressed ; one or two slight folds along the flanks. A dorso- 

 nuchai crest of slightly enlarged keeled or compressed scales, most 

 developed on the nape, sometimes absent on the back. Dorsal scales 

 very small, juxtaposed, smooth or feebly keeled, smaller stiU on the 

 flanks ; ventrals larger, imbricate, smooth. The adpressed hind 

 limb reaches the eye or a little beyond. Tail once and a half to 

 twice as long as head and body, round or feebly compressed, with a 

 small serrated dorsal ridge : caudal scales much larger than dorsals, 

 strongly keeled, spiuose. Colour extremely variable. 



