4 CROTALUS. 



The two lower rows of lateral scales smooth. Third and fourth 

 very faintly carinated. Scales on the back and sides not conspicu- 

 ously different in size except the lower 2 or 3 rows. Posteriorly, 

 near the tail, all the scales are carinated except the lowest. 



General color, yellowish gray, with rhomboidal black blotches, 

 lighter in the centre, and with all the angles perfect. Or rather 

 there is a series of dull yellowish lines crossing obliquely from one 

 side of the abdomen to the other over the back, following the oblique 

 series of scales, and occupying generally the posterior half of each 

 scale, the basal portion being black. These lines, of which there are 

 about 36 crossing from each side, from head to tail, (9 on tail,) 

 decussate first on the 5th or 6th lateral row, and then on the back, 

 where they are more or less confluent three or four rows. The 

 rhomboids thus enclosed and crossing the back are generally black 

 for I2 or 2 scales within the yellowish lines, and the most central 

 portion is dark yellowish brown, mottled with darker. The inter- 

 vals on the sides between the lines are mostly dark yellowish brown, 

 minutely mottled with dark brown. These intervals constitute a 

 lateral series of transverse rhomboids, sometimes with the lower 

 angle truncated. Opposite to the dorsal rhomboids is a series of 

 small triangles in the angles of the first decussation. The distance 

 between two parallel transverse stripes generally consists of five 

 rows of scales, occasionally of six. 



On the sides and posteriorly these markings are more or less in- 

 distinct, though generally recognisable. The tail usually exhibits a 

 ^ood deal of black. The under parts are dull yellowish white, or 

 greenish white, clouded toward the sides with brown. No regular 

 spots visible. The black on the tail does not constitute complete 

 rings, but is interrupted in the middle of the lower surface, and in fact 

 the black patches alternate with each other, and are not opposite. 



The top of the head is light brown, with occasional black scales. 

 A dull yellowish streak starts at the posterior edge of the supercili- 

 ary plate, and passing obliquely backward, through two rows of scales, 

 extends to the angle of the mouth. A second band starts on the 

 plate in advance of the superciliary, and crossing the anterior orbitals, 

 expands till it involves the 7th, 8th, and 9th upper labials. Inter- 

 val between the first two stripes dark brown. There are also indi- 

 cations of a second vertical light bar in front of the nostril, and two 

 below the pit. liostral dark yellowish, lighter in the margin. 

 Charleston, S. C. 169. 32. 27. 48. 5i. Dr. Barker. 



