14 CROTALOPHORUS. 



S. Crofalopliorus tergeniiiiHS, Holbr.— Twenty-five rows of 

 dorsal scales, strongly carinated, with the exception of the first row, which 

 is perfectly smooth. Vertical plate subhexagonal, pointed posteriorly. 

 Seven longitudinal series of blotches. A narrow band of yellowish white 

 extends from the pit to the neck in passing close to the angle of the mouth. 



Syn. Crotalus tergeminus. Sat, Long's Exp. Rocky Mts. I, 1823, 499. — 

 Hael. Journ. Acad. Nat. Sc.'Philad. v. iii, 1827, 372. 



Crotalophorus tergeminus, Holbr. N. Amer. Herp. III., 1812, 29. PI v. 



Crotalophorus, A'Gass. Lake Sup. 1850, 381. PI. vi. fig. G-8. 



Prairie Rattlesnake, Massasauga. 



The ground color above is brown ; the blotches are deep chestnut- 

 brown blackish externally, and with a yellowish white margin. The 

 dorsal blotches are thirty-four in number from the head to the region 

 opposite the anus, twenty-sis of which are transversely and irregu- 

 larly oblong, anteriorly and posteriorly emarginated — less so, however, 

 posteriorly ; eight are subcircular. Five or six exist on the tail from 

 the anus to its tip, extending on the sides, the last two forming 

 sometimes a complete ring. The next series on either side is com- 

 posed of small blotches, but as intensely colored as in the other 

 series. They alternate with the dorsal ones. They have no regu- 

 larity either in outline or position. The second lateral row is com- 

 posed of the largest lateral blotches. They are transversely oblong 

 or oval on the second, third, fourth, fifth, and sixth rows of scales, and 

 opposite the blotches of the dorsal series; consequently alternating 

 with the third series above. The first lateral series again is com- 

 posed of blotches intermediate in size between those of the third 

 and second series ; they occupy the first and second rows of scales, 

 and extend somewhat to the abdominal scutellas, and alternatins: 

 with the adjoining series. Two undulated vittse extend from the 

 supraorbital plates along the neck to the first dorsal blotch, and 

 often confkient with the latter. A linear vitta margined with 

 yellowish white extends from the posterior edge of the eye to the 

 sides of the neck; the inferior yellow margin is the broadest, and 

 passes from the pit close to the angle of the mouth, turning forward 

 to the middle of the lower jaw, enclosing a semi-elliptical browL 

 patch. Two elongated yellowish spots may be observed diverging 

 from both sides of the pit to the lip. The cephalic plates are deep 

 chestnut brown ; a transverse light brown baud extends across the 

 head from one orbit to the other. 



