300 REPORT OF NATIONAL MUSEUM, 1S98. 



B. Dorsal scales small, smooth, subequal. Caudal scales larger, keeled, and spinous. 



Collar not denticulate. Tail slender. Some blue on belly. 

 Dorsal scales eq^ual; scales of anus and legs strongly keeled; color olive, witli a 

 black line from sboulder to shoulder across back. Tail crossbarred 

 witli black U. mearnsii Stejneger. 



C. Scales on the back and sides all small, increasing very gradually from the sides 



to the dorsal line, where there is an obsolete oarination. Tail slightly 

 depressed toward base with enlarged keeled scales. No blue on the 

 belly. Sides with a round black spot behind the fore leg. Back 

 with ten series of blotches, and two light stripes on each side. 

 Ujiper lateral fold of skin obsolete behind the arm, the scales on the 

 crests of the folds scarcely larger. Tail, 1^ times the body. 



Dorsal blotches encircled by blue dots which are sometimes scattered irregu- 

 larly. Sides dusky between the indistinct greenish white lines; 

 below this sometimes with vertical light bands. 



U. stanshiiriana Baird and Girard. 



"Larger, fore legs longer; scales on edge of collar much smaller; bluish drab 

 above with numerous small whitish dots, two or three scales large, 

 scattered over the body; no dusky markings; blue blotch behind 

 axilla" U.palmerii Stejneger. 



D. Middle of back, with 4 to 6 rows of very large rhomboidal, carinated scales, com- 



mencing some distance from the head and running to the tail. The 

 remaining scales on either abruj^tly much smaller and almost granu- 

 lar. Tail compressed from the base. Two very distinct lateral folds 

 of skin along the neck and body. Tail lengthened, compressed. Col- 

 oration, ashy brown. Sides with transverse, dusky bands, separated 

 along the Ijack, and a more couspicuous one on either side the neck. 

 Entire sides of belly in male pale blue, dotted with whitish. 

 a. Dorsal scales in iive or six irregular series, four larger, the scales intermixing 

 and varying in size, although the central ones are smaller than the 

 external, but the outer smaller than that internal to it. 

 Head short, depressed, broad, nearly twice as wide as deep; enlarged scales on 

 sides; hind legs shorter than from vent to collar; a lateral series of 



enlarged scales U. ornata Baird and Girard. 



No lateral series of enlarged scales ; tail less than twice length of head and 



body; olivaceous and without spots above U. leris Stejneger. 



(la. Dorsal scales in four regular series, two on either side of the median smaller 



ones; continued regularly. Enlarged lateral scales in a series. 



Head short, depressed. Head one and a half times as wide as deep. Hind 



leg equal or longer than from vent to collar. General color, light 



brown; the belly quite white. Tail, li times the head and body. 



U. symmetrica Baird. 



Head pointed, narrow; nearly or qiiite as high as wide. General color, nearly 



black, scarcely lighter beneath; back with small blue spots; tail 



banded laterally with the same U. schoUii Baird. 



aaa. Dorsal scales with one princii^al larger row on each side of smaller ones on 

 the median line. A lateral band of larger scales. 

 Dorsal median line with flat scales; frontal i)late transversely divided; no 

 frontoparietal plates; gray with black spots above. 



U. lateralis Boulcnger. 



Dorsal median line with flat scales; frontal plate transversely diviiled; a 



crest of acute scales above the tympanum ; above blue, with two 



rows of spots U. auriculata Cope. 



aaaa. Dorsal scales with irregular larger rows ; larger scales of sides irregularly 

 distributed. 



