188 OP HID I A. 



Spec. Char. — Dorsal rows of scales, twent j-five ; exterior one smooth 5 

 second and third, obsoletely carinated. Tail, and posterior portion 

 of body, with sixteen or seventeen black half-rings. A series of 

 brown dorsal hexagons or octogons, separated throughout by a nar- 

 row light line. A light stripe from the supraocular crosses the 

 angle of the mouth on the third and fourth series of supralabials. 



Syn. -^Crotalm lucifer,B. & G. in Proc. Acad. Nat. Sc. Philad. VI,.1852, 177.— 

 B. & a. Catal. of N. Amer. Rept. I, 1853, 6. 



Descr. — The head is very broad anteriorly, its outline being but 

 slightly tapering forwards in an upper view. Its upper surface is 

 covered with many small and tuberculiform scales, exhibiting a sub- 

 stellated aspect. The interval between the supraocular plates is filled 

 with small scales, nearly equal sized, except upon the row adjoin- 

 ing these plates, in which they are very small. The scales upon the 

 frontal region, in advance of the supraoculars, are variable in number, 

 size, and shape ; in one specimen, there are two rows of four each, of 

 considerable size ; in another, they are fewer, larger, and more irregu- 

 lar. The rostral plate is high, subconical, or subpentagonal. The pre- 

 nasal is subangular, larger than the postnasal, in the anterior edge of 

 which the nostril opens. The prenasal is contiguous to the rostral 

 and anterior upper labial. The eye is proportionally small, and pro- 

 tected superiorly by a large and oblong plate, the supraocular, the 

 edge of which is slightly thickened. Immediately in advance of the 

 eye, there is an elongated subquadrangular loral (or anteorbital), sepa- 

 rated anteriorly from the postnasal by two small scale-like plates. 

 Beneath it we observ^e a smaller and subtriangular plate, limiting the 

 upper edge of the facial pit, the lower edge of which pit is bordered by 

 very small plates. The temporal shields are large, flat, and smooth. 

 There are fourteen upper labial plates on either side, resembling in 

 shape and structure the temporal shields. The lower labials are six- 

 teen in number on either side, also ; the posterior twelve are slightly 

 higher than long, contrasting somewhat with the scales immediately 

 beneath. The symphyseal is triangular and conspicuous ; the adjoin- 

 ing first labial is the most elongated of all, and meets its fellow under 

 the chin, thus completely inclosing the symph3^seal. The second, 

 third, and fourth labials are larger than the rest. There is but one 

 pair of mental shields, very large, and suboblong. The scales on the 

 throat are elongated, subelliptical, and smooth. 



