POISONOUS SNAKES OF NORTH AMERICA. 419 



ities. Vertical i^late [froutal] subcordiform, occipital [parietal] oblong 

 and elongated. A narrow white line commences at the lowest point of 

 tlie orbit and passes obliquely backward to the angle of the mouth. 

 Ground color dark grayish ash, minutely mottled. A series of 38 to 45 

 subcircular dorsal blotches extending from head to tail, dark brown, 

 each with a narrow, distinct yellowish border. Interval rather nar- 

 rower than the spots themselves. A broad band of purplish red passes 

 from head to tail through the blotches. On each side may be distin- 

 guished three series of blotches, the first on the first and second lateral 

 rows of scales and i)artly on the abdominal seutelhe [ventrals or gas- 

 trosteges] ; the second alteruating with this on the second, third, fourth, 

 and fifth rows of scales, and opposite the dorsal series; the third alter- 

 uating with the second and the dorsal series on the fifth, sixth, seventh, 

 and eighth rows of scales. The latter series is dusky and obsolete; the 

 others are uniform and distinctly black. 



The shape of the blotches is subjected to some variation, according 

 to individuals. Generally subcircular or slightly oblong, they become 

 sometimes a transversely elongated quadrangle, three times as long as 

 wide. Their shape varies according to the region of the body ou which 

 they are found. On the anterior third they are subquadrangular, 

 anteriorly and posteriorly emarginated; on the middle region they elon- 

 gate, and toward the posterior third become nearly circular. Backward 

 of the arms the five or six blotches of that region extend on the sides, 

 without, however, meeting on the lower surface. The blotches of the 

 first lateral row are subquadrangular and a little snuiller than those of 

 the second and third rows, the blotches of the second row being trans- 

 versely oblong and largest on the middle region of the body. Side of 

 the head purplish brown, a narrow, distinct white line from tl\e lowest 

 part of the orbit passing obliquely backward to the angle of the mouth. 

 Above and continuous with that white line a deep chestnut-brown 

 vitta is observed, of the same length but broader, and lined above 

 with a narrow, dull, yellowish margin. Two undulated dark brown 

 vitta' extend from the vertex to the first dorsal blotch and confluent 

 with it. A donble crescentic blotch is observed on the frontal scutelliB 

 [internasals and prefrontals], leaving a transversal fulvous band across 

 the head between the orbits. Tlie color underneath is reddish yellow, 

 marmorated with brownish black blotches and minute dots. 



The scales are elongated, carinated, and acute posteriorly. Those of 

 the lateral row are slightly carinated also, but narrower than in C. 

 Gonsors, and more acute posteriorly. 



Number of ventrals [gastrosteges],132 to 13G; of caudals [urosteges], 

 27 to 36; scale rows, 21 to 23. 



The greatest number of joints to any rattle of this species in the 

 U. iS. National Museum is nine. 



Variation. — While the scutellation of this species appears rather 

 constant, there is considerable variation in color, inasmuch as speci- 



