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Genus SCELOPORUS, Wieg. 



Sceloporus, Wiegmann, 1828, 77, 369; Boulenger, 1885, 29, ii, 216. 



Body depressed ; tail long. Head with the plates of the upper surface 

 well developed ; the most posterior and median one (occipital) largest. 

 No bony spines on head. Anterior teeth simple, the lateral tricuspid. 

 Tympanum distinct, sunken. No gular folds. A series of pores (fenjoral) 

 on the under side of the thigh. Scales overlapping and about equal in 

 size. Contains about 25 species inhabiting North and Central America. 



Sceloporus undulatus, (Bosc). 

 Alligator Lizard ; Pine Tree Lizard. 



Agama undulata, Bosc, 1803, 69, iii, 384 ; Tropidolepis undidatus, Hol- 

 brook, 1842, 54-, ii, 73, pi. 9 ; Sceloporus undulatus, Fitzinger, 1843, 

 82, 75 ; Boulenger, 1885, 29, ii, 227. 



Head broad and flat, tapering to the short and rounded snout. Neck 

 moderate, without gular fold. Tail considerably longer than the head 

 and body, and slender. Head with the plates of the upper surface 

 rather large. A series of these over each eye. Back of the head with 

 three plates, the median (occipital) larger than the lateral (parietal), and 

 with a central translucent spot. Anterior border of the ear denticulated 

 with three or more scales. 



Hinder limb pressed to the side reaching about to the ear. Distance 

 from the base of the fifth toe to the tip of the fourth greater than from 

 the tip of the snout to the ear. Under side of the thigh with a row 

 of from 13 to 17 pores. Dorsal scales conspicuously keeled, the keel 

 running out into a sharp point. Ventral scales sitialler and smooth. 

 Scales of the sides forming rows that run upward and backward. There 

 are from 38 to 50 scales around the body and about 35 from the occiput 

 to the base of the tail. The tail is covered Avith large scales, with the 

 keel running obliquel}^ and ending in a point. 



The color above is olive or brownish, sometimes almost black. Across 

 the back are undulating lines of dark brown or black. On each side of 

 the back there is a row of whitish spots. The tail is cross-lined with 

 black. Sides mottled with black, and with some whitish spots. The 

 male has a green or dark blue spot on each side of the throat, sometimes 

 almost black The color is prolonged on to the arm. Each side of the 

 abdomen is green or steel blue. The front of the thigh is dark blue or 

 black. Middle line of the belly yellowish, with mottliugs of black. The 

 female has the throat blue, the abdomen yellowish, Avith black markings.. 

 Dr. C. C. Abbott says that the colors are not indicative of sex. 



The length of this species becomes about 6 inches. 



