109 



Ground color above and on the sides a pale yellowish brown, slightly bluer 

 on the head and appendages ; whole upper surface covered by a series of whitish 

 spots, these forming sixteen longitudinal rows on the back and sides, a few of 

 the spots on the sides of the neck fusing to form the beginnings of a stripe; 

 ventral surface whitish, yellowish pink on the chin and appendages, the color 

 tending to rosy on the tail and lower legs; indistinct spotting of a bluish tone 

 at the bases of the abdominal scutes; granules of the throat slightly bluish. 



Measurements. — Total length, 422 mm.; head and body, 106; arm, 41; leg, 

 84; head length, 26; head breadth, 16. 



This was a common species and a considerable series of speci- 

 mens was preserved. 



Polychroides, new genus. 



Diagnosis. — Body strongly compressed, covered with keeled, imbricating 

 scales of moderate size; head with large swollen scales tending to be bluntly 

 keeled; tympanum distinct; a gular fold present in both sexes but larger in the 

 male, this foldTringed anteriorly with elongate scales; digits compressed, four 

 enlarged scales at the base of the claw; ventral lamellae of digits with a series 

 of small keels to each scale; third and fourth toes subequal; femoral pores 

 present in both sexes; tail very long, slightly compressed at the base; teeth 

 tricuspid, the premaxillary teeth only faintly so; no pterygoid teeth; no sternal 

 fontanelle; abdominal ribs. 



Tyye. — Polychroides peruvianus, new species. 



Remarks. — The generic status of many of- the slow-moving 

 arboreal iguanids is very uncertain. The species described below 

 cannot be referred to either Enyalius, Enyalioides or Polychrus 

 as at present defined. It seems most closely related to Polychrus 

 with which it agrees in its femoral pores, large head scales, 

 subequal third and fourth toe and its sacculated lung. I have 

 seen both Polychrus and Polychroides alive and have been struck 

 by their great similarity in behavior. The pronounced nuchal 

 crest of the latter readily distinguishes it from the former. 



Polychroides peruvianus, new species. 



Diagnosis. — A compressed, long-tailed Polychrus-like iguanid, 

 having a pronounced nuchal crest and a dorsal crest in the male; 

 a pronounced gular fold present, denticulated anteriorly with 

 enlarged scales; a pronounced sexual dimorphism, — the males 

 with the higher dorsal crest, enlarged femoral pores and with a 

 whitish or yellowish head; the females without a dorsal crest, 

 with ill-defined femoral pores and with a dark-brown or greenish 

 head striped on the sides with white. 



Distribution. — Wooded valleys of the Andes of northern Peru, 

 extending through the province of Cajamarca and part of Piura; 

 specimens taken near Bellavista and Querocotilla. 



Type. — Adult male, No. 17,973, Museum of Comparative Zoology; valleys 

 near Querocotilla, province of Cajamarca, Peru. September, 1916. G. K. Noble. 



Description of type. — Head large, greatest width of head contained one and 

 two-thirds times in the greatest length; can thus rostralis very pronounced, 

 continued posteriorly into a supraciliary and temporal ridge, the scales of this 

 ridge swollen but not forming a denticulation ; nostril piercing a single scale, 

 immediately ventral to the anterior end of the canthus rostralis; distance be- 



