174 IGUANID 2. 
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. 
Lophyrus araucanus, Lesson, Voy. Coquille, Rept. pl. ii. fig. 1. 
Stellio peruvianus, Less. 0. c. fig. 2. 
Tropidurus microlophus, Wieym. Nova Acta Ac, Leop.-Carol. xvii. 
1835, i. p. 223, pl. xvi. 
—— heterolepis, Wiegm. 1. c. p. 225, pl. xvii. fig. 1. 
Microlophus lessonii, Dum. § Bibr. iv. p. 3386; Gutchen. in Gay, 
Hist. Chile, Rept. p. 48. 
Steirolepis microlophus, Fitsing. Syst. Rept. p. 72. 
—— heterolepis, Fitzing. 1. c. 
—— peruviana, Fitzing. lc. p. 73. 
—— xanthostigma, Tschudi, Faun. Per., Herp. p. 29. 
tigris, Tschudz, 1. c. p. 30. 
—— thoracica, Tschudi, 1. c. p. 31. 
—— quadrivittata, Tschudi, l.c. p. 32. 
Microlophus peruvianus, Girard, U.S. Explor. Exped., Herp. p. 314; 
Cope, Journ. Ac, Philad, (2) viii. 1876, p. 178. 
heterolepis, Cope, J. c. p. 171. 
inguinalis, Cope, l.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- 
nuchal 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 still 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 dorsuls, 
strongly keeled, spinose. Colour extremely variable. 
