S A U R I A. 



of the limbs is barred with black. The abdomen is yellowish or dull 

 whitish, unicolor in the female, whilst in the male, the sides exhibit 

 au elongated blue patch, slightly margined with blackish, and leaving 

 quite a wide area uncovered upon the middle region. The inferior 

 surface of the head and the chest are mottled with bluish in both 

 sexes, more conspicuously, however, in the male than in the female. 



LOG. Specimens of this species were collected in Oregon. 



Plate XX, fig. 1, represents the male sex of Sceloporus gracilis, size 

 of life. 



Fig. 2, is an under view of the same individual. 



Fig. 3, a profile view of the head ; 



Fig. 4, the head, seen from above ; 



Fig. 5, a front view of the head. 



Fig. 6, the left hand, seen, from above. 



Fig. 7, the interfemoral and cloacal regions, with the posterior left 

 limb, from beneath. 



Fig. 8, a group of dorsal scales ; 



Fig. 9, a group of abdominal scales. 



Figs. 3-9, are somewhat magnified, to render the details of their 

 structure more apparent. 



GENUS PHRYNOSOMA, WIEQM. 



GEN. CHAK. Vertex region of the head elevated, with an even or 

 depressed surface; temporal and occipital regions spinous. Cephalic 

 plates small, polygonal, and subequal ; occipital plate subcircular. 

 Maxillary teeth small and subconical. Palate toothless. Tongue 

 subelliptical, depressed, thick, papillous, and fleshy posteriorly, thin 

 and leathery anteriorly. Sides of the neck rumpled ; throat trans- 

 versely wrinkled. Auricular apertures simple, granular, or denticu- 

 lated in front ; occasionally entirely hidden under the skin. Body 

 rather short, or moderately elongated, very much depressed, broad, 

 subovate or subelliptical, generally provided, on either side, with 

 one, two, or three series of subpyramidal scales at the periphery of 

 the abdomen. Its upper surface is scattered all over with subtri- 

 angular, scaly, sometimes erect tubercles, in the midst of small, 



