CROCODILIANS, LIZAKDS, AND SNAKES. 301 



Median dorsal scales granular ; frontal undivided ; frontoparietal plates pres- 

 ent; brown above, dark spotted U. bicarinala Dumeril. 



Median dorsal scales granular; frontal plate undivided; frontoparietals 

 present; greenish gray with black cross band above. 



U. irregularis Fischer. 

 aaaaa. Larger dorsal scales in live or six regular series of nearly equal size. 



Frontal plate undivided; larger dorsal rows fewer; caudal scales much 

 larger than ventrals, strongly keeled; dark brown with black 

 cross-bands; tail, blackish; gular color orange.. U. nigricauda Cope. 



Frontal plate undivided; dorsal scales smaller, graduating into granular 

 laterals ; gular color blue U. parciscuiata Van Denburgh. 



Body very slender; head narrow and elongated, but wider than high. An 

 additional row of plates on the rostum; frontal jilate divided; 

 tail, two and one-half times or more the head and body; general 

 color light reddish gray; the bands distinct., l'. graciosa Hallowell. 



The geuus Uta belongs to the Nearctic Fauna, only two species 

 {U. hicarinata and F. auriculata) extending beyond its limits. In the 

 Nearctic Fauna it is nearly restricted to the Sonorau district. It does 

 not occur in the Eastern nor Austroriparian, and one species only 

 ranges from the Sonoran into the Pacific ( U. stanshuriana). One 

 species is confined to the St. Lucas region ( U. thalassina), and another 

 i-auges from that center to the Pacific ( U. nigricauda). From the 

 iSonoran two species range into the Great Basin, U. stanshuriana and 

 U. graciosa, the former of them extending- far northward. One species, 

 V. mearnsiiy is found near the south border of California, while two 

 others belong to different jjarts of the peninsula of Lower California 

 {U. repens and V. parviscutata). The f7. attricwZato is from the Revilla- 

 gigedo Islands, a region Avhose faunal relation is doubtful, but is prob- 

 ably with the iSTeotropical Realm. 



UTA THALASSINA Cope. 



Uta thalassina Copk, Proc. Acad. Nat. Sci. Phila., 1863, p. 104. 

 I'etrosaurm thalassinus Boulenger, Cat. Liz. Brit. Mus., II, 1885, p. 205. 



Form much depressed. Median dorsal scales larger, smooth, gradu- 

 ating into the lateral, smaller than those of the abdomen, not sepa- 

 rated by median smaller ones. Abdominal scales nearly rectangular, 

 in transverse series. Brachial scales a little larger, more imbricate, 

 keeled. Occipital plate large, longer than broad, triangular, with 

 rounded angles, separated by two plates from those bounding supra- 

 orbital region. One series of interorbitals. Supraoculars in three 

 series, five in the interior largest. Internasals, two series of four, each 

 followed by two pairs. Scales of the collar but little larger than those 

 anterior; gular scales equal. A narrow entire suborbital. Eight 

 superior labials, bounded above by two series of similar plates. 

 Eight oblong inferior labials. Symphyseal larger, followed by two 

 trapezoid infralabials. A scapuloinguinal dermal fold on each side. 

 Extended posterior extremity reaching anterior border of ear orifice. 

 Tail broad and depressed at base, slender and slightly compressed, 



