SYNOPSES AND DESCRIPTIONS. 13 



pairs, second half as large as first. Scales in 15-17 rows, some of the 

 dorsals with keels. Anal entire. Subcaudals in two rows. 



Dark brown or black. The light color of the throat and chin-shields 

 extends upward as an occipital collar. Flanks with widely separated, 

 wedge-shaped, vertical bars of light color, which frequently meet in their 

 points on the back, forming transverse bands to the sides of the belly. 

 Belly much spotted with dark posteriorly, 



Hab. Mexico and Central America, 



Leptognathus dumerilii. 



Jan, 1870, Icon. Livr. XXXVII, pi. V, fig. 2. 



Scales smooth, in 17 rows. The principal difference between this species 

 and the preceding is in the carination of the scales. It is altogether likely 

 that individual variations in this respect will do away with its value, in 

 which case the form cannot even stand as a variety. 



Leptognathus nebulatus. 



Petalognathus nebulatus Dumeril, 1852 (1853), Mem. de VAcad. Sci. XXIII, 466. 



Slender, elongate, much compressed ; head large, distinct, crown slightly 

 convex, muzzle high ; tail slender, tapering. Eye large, pupil erect. Head- 

 shields short, broad. Rostral as broad as high. Nasal in two parts, nos- 

 tril principally in anterior. Loreal and preocular fused. One preocular, 

 sometimes a small plate at its lower posterior angle. Postoculars*two. 

 Temporals 1+24-3. Labials seven, fourth and fifth below the eye, sixth 

 largest. Infralabials nine, sixth lai'gest. Submentals three pairs (2 — 3), 

 anterior larger. Scales smooth, in 15 rows, several of the dorsal broader, 

 the median broader than long. Ventrals 185 — 197. Anal entire. Sub- 

 caudals 87 — 90. pairs. 



Greyish-brown, mottled with brown, with more or less irregular narrow 

 transverse white-edged bands of brown. A series of large blotches on each 

 side of the abdomen, apparently separated at the median line, more or less 

 confluent with the dorsal bands, and frequently with them forming com- 

 plete rings around the body. Belly yellowish, clouded and spotted with 

 brown. Head brown, irregularly marked with white (yellow). First 

 brown band immediately behind the head. Tail darker. Total length 

 17 inches; tail 4, Total length 14| in.; tail 3|. Hab, Mexico to Brazil; 

 'West Indies. 



