SERPENTS. 



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Genus C R O T A I. U S,* Linn. ,^rfi^Op0- t^^r 



Gen. Char. Upper surface of head covered with small plates, 

 scale-like, with a few larger ones in front. The tail is terminated 

 by a well-developed rattle. A deep pit between the eyes and the 

 nostrils. Subcaudal scutellae entire. Temporal and labial shields 

 small and convex. 



» 

 1. CrotalMS dui'issus, Linn. — Head angular. Scales between the 

 superciliaries small, numerous, uniform. Plates above snout, 2 anterior 

 frontal, and 5 postfrontal. Suborbital chain continuous, of large scales. 

 Two rows between this and labials. Labials 12-14 above, 5th largest; 13-15 

 below. Scales on the back 23-25, all carinated ; carination on outer row 

 obsolete. Tail black. Above sulphur-brown, with two rows of confluent 

 brown lozenges. Light line from superciliary to angle of the mouth. Be- 

 hind this a dark patch. 



Stn. Crotalus durissus, Linn. Syst. Nat. I. 1766, 372. — Gm. Linn. Syst. 

 Nat. ed. xiii. L, III. 1788, 1081.— Holbe. N. Amer. Herp. IIL 1842, 9. PI. i. 

 — Dekay, New Y. Fauna. Pt. III. 1842, 55. PI. ix., fig. 19.— Stoker, Rep. 

 Kept, of Mass. 1839, 233. 



Vipera caudisona americana, Catesb. Nat. Hist. Carol. II. 1743, 41. PI. Ixi. 



Banded Rattlesnake. 



Head above covered with small subtuberculous scales. Supercili- 

 aries large. Anterior frontals large, triangular, emarginated behind 

 to receive a series of three small plates. A single subhexagonal plate 

 between the superciliary and anterior frontal. The exterior plate of 

 the posterior frontal row is much the largest, and is in contact with 



* The names and characteristics of the higher divisions will be given in the sy- 

 nopsis of species. 



The figures at the end of the descriptions refer, the Ist to the number of abdomi- 

 nal scutellaj ; 2d, to the subcaudal scutellse ; 3d, to the dorsal rows ; 4th, to thy 

 total length ; and 5th, to the length of the tail. 



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