60 HETERODON. 



all much higher than broad. Lower labials 9. Curve of upper jaw 

 very convex and short. 



Scales back of the head short, curved, obsoletely carinated. Dorsal 

 rows of scales 25, outer rows smooth, sometimes only three, the cari- 

 nation slight, increasing to the medial row. Scales shorter and 

 broader than in the other type, becoming narrower on the back ; 

 those behind rather narrower than before. Body contracted at the 

 anus, then expanding or swelling on the tail, which is thick through- 

 out, tapering suddenly at the tip. Scales on the tail longer and 

 broader than those of the upper part of the body in front ; carination 

 not very distinct, inferior three rows truncated behind, especially the 

 highest. 



A dorsal series of transverse black blotches, 35 from head to tip of 

 tail, the 27th opposite the anus. These are sometimes oblique, but ge- 

 nerally transverse, and with the anterior and posterior margins paral- 

 lel : they are about 9 scales wide, and three to four long, with light 

 brownish yellow intervals one or one and a half scales wide. On 

 each side, and opposite the intervals, is a distinct series of subquad- 

 rate or circular black spots on the 6th-9th rows, not touching those on 

 the back, and between them a dusky shade opposite the dorsal spots. 

 Below these again are usually two smaller blotches to each spot. 

 Intervals betwe.en the spots mottled yellowish brown. Beneath yel- 

 lowish, with obsolete small brown blotches. On the tail there are 

 9 half-rings, rather wider than the light intervals, and somewhat con- 

 tracted above. 



A narrow black line crosses the forehead, on the posterior half of 

 the postfrontals, and just margining the vertical; this passes through 

 the centre of the eye, and is continued to the postlabial. A medial 

 patch of black expanding behind, starts from the commissure of the 

 occipitals, from which plates others, one on each side, pass across the 

 angle of the jaws, the three confluent with the dark color in the occi- 

 pitals. In //. platyrMnos this medial patch is isolated, and not in 

 contact with the occipital one. 

 Charleston, S. a 117+1.35+9.25. 18. 3 J. C. Girard. 



Some specimens from Abbeville, S. C, vary in having the rostral 

 separated from the prefrontals by two or three small plates, and 

 the azygos entirely cut ofi" from the frontals by intervening plates. 

 The lower wall of the rostral is constituted by two small plates : there 

 is a second small plate above the loral; in fact a general tendency to 



