SONORA. 117 



Genus S O ]\ O R A, Baird & Girard. 



Gen. Char. Head continuous with the body, very much nar- 

 rower on the snout. Cephalic plates normal. Vertical plate narrow 

 anteriorly. Superciliaries proportionally large. One loral. One 

 anteorbital and three postorbitals. Two nasals. Eyes proportionally 

 large. Scales smooth. Postabdominal scutella bifid. Subcaudal, 

 divided. 



Sonora semiannulata, B. & G. — Body above annulated with jet 

 black ; tail completely annulated ; intermediate space wider, orange-red on 

 the dorsal region, greenish on the sides, with bases of scales blackish. Dor- 

 sal scales in 15 rows. 



Snout subquadrangular, elongated. Vertical plate widening pos- 

 teriorly to the occipitals. Occipitals elongated, margin irregular. 

 Postfrontals angular, not reaching the orbit. Prefrontals trapezoidal, 

 two-thirds of the size of the postfrontals. Rostral very much de- 

 veloped. Nostrils in the middle, between the two nasals. Loral 

 elongated, horizontal, angular. Eyes circular. Superciliaries angu- 

 lar, lozenge-shaped. iVnteorbital one, subcrescentic, narrow, resting 

 on the third upper labial. Postorbitals three, angular, upper one 

 largest, produced between the superciliaries and occipitals, and touch- 

 ing slightly the vertical. Three temporal shields, anterior one 

 largest, and angular. Mouth deeply cleft, undulated. Upper labials 

 7 ; nearly equal in size ; first and last smallest. Inferior labials 8 ; 

 4th largest. Body subcylindrical, covered with smooth scales, pro- 

 portionally broad, and forming 15 rows, outer row but slightly 

 broader. Tail tapering to a point. 



Body above crossed with transverse jet-black bars, 25 from head 

 to anus, extending between and involving the exterior rows, becom- 

 ing narrower on the flanks : along the back 3 to 4 scales long. 

 Space between the bars above orange-red, one scale wider than the 

 black bars ; on the sides greenish, with the base of the scales black- 

 ish. On the tail 6 black rings, continuous all around, covering 2 to 3 

 scales ; intermediate space red-orange, 4 or 5 scales wide. Beneath uni- 

 form dull green, the black bars of the body not touching the scutellas. 



Sonora, Hex. 149-f 1. 39. 15. 9 J. If. Col. J. D. Graham. 



