428 REPORT OF NATIONAL MUSEUM, 1893. 



large scales: two rt>ws between this and labials. Labials 12 to 14 

 above, fifth largest; 13 tola below. Rows of scales on the back 2o to 

 25, all carinated : carination on outer row obsolete. Tail black. Above 

 sulphur-brown, with 2 rows of confluent browu lozenges. Light liue 

 from superciliary to angle of the mouth; behind this a dark patch (figs. 

 64, 65). 



Head above covered with small subtuberculous scales. Superciliaries 

 (supraoculars) large. Anterior frontals (internasals) large, triangular, 

 emarginated behind to receive a series of three small plates. A single 

 subhexagonal plate between the superciliary (supraocular) and anterior 



Fig. 04. Fig. 65. 



HEAL) OK CROTALfS HORUIDUS, TOP VIEW. HEAD OF CROTALU:? HORRIDIS, SIDE VIEW. 



( Aft^r n.iir.l. ) (After B.iir.i. ' 



frontal (iuteruasal). The exterior plate of the posterior frontal (pre- 

 frontal) row is much the largest, and is in contact with the super- 

 ciliaries (supraoculars). A series of 3 or 4 large flat scales extend 

 from the posterior extremity of the superciliary (supraocular). Scales 

 on the cheeks (temporals) very large, truncate. Anterior orbitals 

 (preoculars) double; the upper one rectangular, elongated longitudi- 

 nally, separated from the (posterior) nasal by 2 small plates (loreals). 



General color above that of roll sulphur; beneath, whitish yellow. 

 Along the back is a double series of subrhomboidal blotches, looking 

 as if they had been in contact, and then the line of junction partially 

 effaced for the 3 or 4 central rows. (See fig. 52.) The impression 

 conveyed of the color of these blotches is that of coarse mottliugs of 

 soot or gunpowder grains, more crowded exteriorly. There are 21 of 

 these blotches from the head to the anus, the tail being entirely black. 

 The rhomboids are inclosed within about 12 dorsal series of scales. 

 Directly opposite to these spots on each side is a series of subtriau- 

 gnlar blotches similarly constituted as to color, and extending from the 

 abdomen to about the fifth lateral row, and some 6 or 7 scales long. 

 Anteriorly these are distinct from the dorsal series, but posteriorly 

 they are confluent with them, forming a series of zigzag blotches across 

 the body. The scutelhe below show more or less of the grain-like 

 mottlings. Posteriorly the yellow of the body is suffused with darker. 



There are no markings of lines distinctly visible on the sides of the 

 head. In the center of the spaces between the dorsal and lateral series 

 of blotches are indications of small obselete spots, and in some cases 



