716 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiii. 



contact with prefrontals; parietals xQvy short, their length less than 

 frontal and less than twice the length of the interprefrontal suture; 

 interparietal suture much shorter than distance from tip of snout to 

 frontal, eciualing interprefrontal and internasal sutures together; 

 loreal rather large, longer than high; one preocular, narrow below 

 and with a very prominent canthal ridge above; a rather large subpre- 

 ocular; two postoculars; temporals, 2-2-2; eye very large, its horizon- 

 tal diameter equaling its distance from the nostril, and two-thirds the 

 length of the frontal; 8 supralabials, seventh and eighth subequal and 

 largest, fourth and tifth entering eye; 7 lower labials, four in contact 

 with anterior pair of chin-shields; posterior pair of chin-shields about 

 the same length as anterior pair but considerately narrower; scales in 17 

 rows, smooth, with two apical pits; ventrals obtusely angulate laterally, 

 194; anal divided; subcaudals 112. Color al)ove walnut brown, deepest 

 toward the tip of each scale, and with blackish brown narrow linear 

 spots, never longer than a scale, sparsel}" and irregularh^ scattered 

 over the back and sides; head more uniformly pale walnut brown with 

 a few irregularly scattered ])lackish dots, and a few obscure dusky 

 marblings on lores and labials; under side pale, sprinkled irregularly 

 with slate-colored dotlets, which toward the head become more pro- 

 nounced and collected as two parallel longitudinal zones; chin and 

 throat more definitely but irregularly marked with larger spots of the 

 same color. 



Dimensions. — Total length, 1,450 mm.; tail. 300 mm. 



Variatio)!.— In a much younger specimen, Cat. No. 24383, U.S.N.M., 

 about 820 mm. in length, the coloration above is more grayish and 

 entirely uniform, without the blackish spots; the under side is also 

 uniform pale, with no markings except a few dusky dots on the neck; 

 the sides of the head are brownish like the top, with the indication 

 of a dusky longitudinal ])and on the upper half of the supralabials; 

 the lower part of the latter as well as throat j'ellowish; preoculars 

 and postoculars, together with a ])and from the former to the nostril, 

 likewise yellowish. In this specimen the parietals are slightly larger 

 in proportion and the frontal wider. 



In some of the other specimens, intermediate in size between the 

 two specimens mentioned, the dark markings on the chin, throat, and 

 fore neck are very pronounced and the dusky mottlings on the rest of 

 the underside very dense, only leaving a pale line on the angle of the 

 belly, while in others they are condensed into two fairly distinct paral- 

 lel longitudinal bands with a pale zon6 down the middle of the bod3\ 



RemarJiS. — In general appearance this species presents closer analogy 

 to younger specimens of the eastern typical form of Bascmiion fagel- 

 luiii than to B. Jlagellum frenatum., though showing indications of the 

 peculiar facial pattern of the latter. It is, however, well differentiated 



