512 REPORT OF NATIONAL MUSEUM, 1898. 



border of the tympanum fiirnislied with flat or slightly convex scales. 

 Oue pair of prefrontonasals and two small supranasals. Nine to ten 

 pairs of supi^ilabials. Mental divided. Dorsal scales larger than the 

 veutrals and slightly swollen longitudinally. Lateral fold inconspicu- 

 ous. Tail of medium length. General color greenish yellow, with wide 

 black transverse bands. 



Head flat above, depressed in the occipital region, covered with 

 scales having the surface finely rugose; length from the end of the 

 muzzle to the middle of the auricular opening equaling seven or eight 

 rows of dorsal scales, and entering four and one-third times into the 

 space comprised between the chin and the anus. Muzzle short, having 

 two internasal scutes and two small supranasals; the two internasals 

 are in contact in front with the rostral, and on each side with the first 

 supralabial; the two prefrontonasals, of much larger dimension, are 

 hexagonal; the interfroutonasal, which is smaller, is quadrilateral and 

 is in contact in front with the two preceding, and behind with the pre- 

 frontals. The supranasals, very small, are situated oue to the right, 

 the other to the left, between the preceding scutes and the nasal scale. 

 The i)refrontals are hexagonal and are smaller than the prefrontonasals. 

 The frontal is relatively short, obtusely angled in front, with a sharp 

 XDOsterior angle, which is truncate at the extremity by the interparietal, 

 which is rather large, and is in contact in front with the frontal and 

 the frontoparietal, on each side with a large parietal, and behind with 

 three very narrow occipitals. The latter are followed by two rows of 

 convex nuchal scales. Each of the supraocular demicircles is protected 

 by eight projecting scales (five large and three exceedingly small) and 

 is bordered exteriorly by a series of fine superciliary scales, of which 

 the first is more developed than the others. Nostril pierced in the 

 posterior part of the nasal plate; this latter is subrectangular and is in 

 contact before with one of the internasals; above with the supranasal 

 and upi)er nasoloreal, below with the first two supralabial plates, and 

 behind with the inferior postnasal. 



The loreal scutellum is rhomboidal and rests on a part of the third 

 and fourth supralabial; the second loreal is large and irregularly hex- 

 agonal; the preocular is subquadrilateral and precedes two suboculars. 

 There are nine or ten supralabials; the first seven or eight are ([uadri- 

 lateral, the following, rather higher, is pentagonal, and the last, a long 

 one, has a sharp angle directed backward; the nine pairs of inferior 

 labials are well developed. Aperture of the ear triangular, overhung 

 by the projecting temporals, and bordered in front by three or four 

 small convex scales and behind by Sfaly grains. Mental divided and 

 succeeded on the right and left by four plates ; those of the first pair 

 in contact on their inner borders, and the outer borders of all separated 

 from the inferior labials by one row of scales. The throat scales are 

 flat and closely resemble those on the breast; on the sides of the neck 

 they are tubercular; but the region above, between the ear and arm, is 



