76 SYNOPSES AND DESCRIPTIONS. 
head, between the bands from the occiput, which spread around it, there is 
a median short longitudinal band of half their length. Mississippi Valley 
to the Atlantic. 
var. NIGER. 
ScyTALE NIGER Daudin, 1803, Hist. Rept., V, 342. 
HETERODON PLATYRHINOS, var. NIGER, Jan., 1863, Elenc. Sist. 
Dark brown or olivaceous to uniform black. 
H. catesbyi of Dr. Giinther is not separated from HH. nasicus by the 
description. Southeastern States. 
HEtTeRopon simvs, pl. VI, fig. 4. 
Cotuser stuus Linné, 1766, Syst. Nat., ed. XI, 375. 
Hereropon stuus Holbrook, 1842, N. A. Herp. IV, 57, pl. XV. 
Stout, tapering backward, belly flat, body, neck, and head very disten- 
sible. Head broad, short, slightly convex on the crown; tail short, near 
one sixth of the total, thick, tapering. Eye large, pupil round. Mouth- 
cleft moderate, forming with the face of the rostral a continuous curve. 
Posterior maxillary teeth isolated, larger, smooth. Crown-shields broad. 
Parietals, frontal, and prefrontals frequently cut into smaller plates. 
Supraciliaries broad. Azygos shield (behind the rostral) surrounded, and 
the internasals separated from the rostral, by small plates. Rostral broad, 
very prominent, produced obliquely upward and expanded into an acute- 
edged spade-shaped trihedral, sharp-ridged on the top of the snout. Nasal 
in two parts, sometimes three; nostril valvular. Loreals two, upper 
smaller. Oculars LO—13. Temporals 4+5, varying much. Labials eight, 
sixth and seventh large. Infralabials ten (9—11), fourth largest, four in 
contact with the submentals. Submentals one pair, short. Scales keeled 
in 25 (23—27) rows, medial narrow, lateral and caudal broad and 
rounded. The outer row is keeled in some, smooth in others, and in 
cases the keels are very indistinct on two or three rows above it. 
Yellowish-brown to brownish-yellow. Pattern of coloration similar to 
that of //. platyrhinus, with a dorsal series (830—50) of large blotches; 
alternating with this on the upper part of the flank a series hardly half as 
large; below the latter, on the side, are three or four alternating series— 
more or less irregular and confluent—of small spots, the lower being upon 
the ends of the ventrals. Belly yellow, more or less clouded with brown, 
