Vol. II, Pt. I] VAN DENB URGH—SLEVIN—GALAPAGOAN LIZARDS 147 



General remarks. — The Abingdon Island Tropidunis is a 

 very distinct species. It has smaller scales than any other 

 species found in the archipelago. In scale characters it most 

 resembles the species of Duncan Island, but has rather smaller 

 scales and a very different coloration. The peculiar light 

 speckling of the upper surfaces, and particularly of the head, 

 seems to be quite characteristic, and is shown by both sexes. 



Tropidurus duncanensis Baur 

 Duncan Island Lizard 



1889, Tropidunis grayi, Cope, Proc. U. S. Nat. Mus., XII, 1889, p. 145 

 (part) ; Boulenger, Ann. and Mag. Nat. Hist, (6), VII, 1891, p. 502 

 (part). 



1890, Tropidurus duncanensis, Baur, Biol. Centralbl., X, 1890, p. 479 

 (type locality Duncan Island Galapagos Archipelago) ; Baur, Fest- 

 schrift fiir Leuckart, 1892, p. 270; Heller, Proc. Washington Acad. Sci., 

 V, 1903, p. 77. 



Diagnosis. — Sides of neck with numerous folds; skin be- 

 tween neck folds granular; hind legs without definite blackish 

 spots; interparietal usually much broader than long; 76 to 

 92 scales around middle of body; top of head unicolor; no 

 middorsal streak; often much red in coloration. 



Types.— U. S. National Museum Nos. 14941 to 14944. 

 Collected by the U. S. Fish Commission Steamer "Albatross," 

 on Duncan Island, Galapagos Archipelago, between April 4 

 and 16, 1888. 



Distribution. — Duncan Island, Galapagos Archipelago. 



Material. — The Academy collection contains about one 

 hundred specimens, of which thirty-nine males and forty-eight 

 females have been included in the scale counts. 



Description of adult male No. 12203. — The head is covered above with 

 smooth scales; interparietal largest, broader than long; four or five su- 

 perior and as many inferior labials, to below middle of eye ; rostral very 

 broad and low ; symphyseal much narrower, followed by a series of large 

 sublabials, of which all but the first are separated from the infralabials 

 by a row of somewhat smaller plates. Ear-opening large, with an an- 

 terior denticulation of six or eight long, slender scales. Side of neck be- 

 tween ear-opening and fore limb with numerous folds, covered with 

 granular scales. A strong antehumeral, but no complete gular, fold. A 

 well-developed median dorsal crest begins four scales behind the inter- 

 parietal, and runs continuously to and along the tail, being highest on the 

 proximal third of the tail, and absent toward its tip. The dorsal regions 

 of the neck, body, and tail are covered with rather small, keeled, mucronate 

 scales, which, on the body, change gradually to smaller, keeled, mucronate 

 laterals. These again change gradually into the smooth ventrals, which are 

 much smaller than the dorsals. The gular scales are smooth, smaller 

 posteriorly, smallest below the ear. The scales on the chest are about as 

 large as the dorsals, smooth and imbricate. The limbs are provided above 



