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 Daiulln, 1803, Jlisf. Rcpt., V, 042. 



Heteeodon PLATYKUiNOs, var. NIGER, Jaii., 1863, Elenc. Sisl. 



Dark brown or olivaceous to uniform black. 



H. cateshyi of Dr. Giinther is not separated from //. nasicus by the 

 description. Southeastern States. 



Heterodon simus, pi. VI., ficj. 4. 



Coluber simus Limit; 1766, Syst. Nat.., cd. XII, 375. 

 Heterodon snius Holbrook, 1842, N. A. Ilerp. IV, 57, pi. 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 obli(piely 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 10—13. Temporals 4-1-5, 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 otiiers, and in 

 cases the keels are very indi.stinct on two or three rows above it. 



Y('ll(jwish-brown to l)rownisli-y<'llow. Pattern of coloration similar to 

 that of //. plafyrhinus, with a dorsal series (30 — 50) of large blotches; 

 alternating with this on the ui)i)er 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, mure or less clouded with brown, 



