458 



BULLETIN 58, UNITED STATES NATIONAL MUSEUM. 



crescentic, nearly reaching the lower preocular below the eye and 

 separating the latter from fourth supralabial; 2+4 temporals, of 

 which the lower ones in each row are large hexagonal flat shields, 

 those above being small scales, keeled on the row nearest the parietals: 

 the lower temporal of the third row large and shaped like those in 

 front of it; these three lower temporals form a series of large shields 

 larger than the adjoining labials; 7 supralabials, second smallest, third 

 and fourth largest, and those behind gradually decreasing in size, 

 third just entering eye; five lower labials in contact with anterior 

 chin-shields, which are much larger than the second pair, the latter 

 being scarcely differentiated from the scales beliind and between 

 them; 21 rows of strongly keeled scales with a pair of apical pits; 

 142 ventrals; anal undivided; 45 subcaudals, all divided. Color (in 

 alcohol) above brownish gray with a series of large, rhomboid, darker 



363 



Figs. 362-364.— Agkistrodon blomhoffii. IJ X NAT. size. 362, top of hE-\d; 363, side of head; 

 364, underside of head. No. 31867, U.S.N.M. 



browm, black-edged blotches on each side close to the median 

 dorsal line, alternating, often confluent, descending on the sides to 

 the outer scale row, separated by a narrow^ paler grayish band the 

 edges of which nearest the black margin of the dark blotches incline 

 to whitish; top of head of lighter brown, with a dark irregular mark- 

 ing on each shield; a sharply marked blackish browm stripe on lower 

 preocular through eye where it widens to a very broad band on the 

 temples, passing across the last supralabial at the corner of the mouth, 

 the sharp edges of this band emphasized by a narrow white line above 

 and below, the one below having a small sharply defined white spot 

 on the anterior angle of the long crescentic lower postocular; under- 

 side irregularly mottled with whitish and blackish in about equal 

 proportions; tip of tail bro^\^lish white. 



Diniensions. 



mm. 



Total length 513 



Snout (o vent 438 



Vent to tip of tail 75 



