14 SYNOPSES AND DESCRIPTIONS. 



Leptognathus DIMIDIATUS. 

 Gimther, 1872, Ann. & Mag. Nat. Hist., IX, 31. 



Long, slender, much compressed ; head broad, short ; tail less than one 

 third of the total length. Eye rather large, pupil erect. Internasals 

 small. Prefrontals large, bent down on the face, entering the orbit. Outer 

 edges of frontal nearly parallel. Loreal and preocular fused. Post- 

 oculars two. Temporals 1+2. Submentals three pairs, anterior largest, 

 crescent-shaped; middle longer than broad, posterior divergent. Labials 

 eight, fifth and sixth in orbit. An azygos scale-like shield under the chin, 

 surrounded by the first pair of infralabials, the mental and submentals. 

 Second to sixth infralabials in contact with anterior submentals. Scales 

 smooth, in 15 series, vertebral not larger. Ventrals 186. Anal entire. 

 Subcaudals 98 pairs. 



Body and tail with broad black rings, separated by narrow, whitish inter- 

 spaces. Twenty-five rings on the trunk, sixteen on tail; white interspaces 

 subdivided by a narrow black transverse line. Upper parts of head black ; 

 with small, irregularly placed whitish spots, and a pair of large spots of 

 the same color on the neck, forming a sort of collar. Anterior chin-shields 

 black. (From Griinther.) Hab. Mexico. 



Dipsas. 



Laurent, 1768. 



Slender, elongate, compressed; head very- large, distinct, depressed, 

 broad behind, angles rounded, muzzle blunt; tail slender, tapering. Eye 

 moderately to very large, pupil erect. Posterior maxillary teeth longer, 

 grooved. Rostral broad, low. Head-shields nine, broad. Nasal divided. 

 A loreal, rarely fused with oi'bital. One preocular. Postoculars two to 

 three. Scales smooth, rarely keeled, in 19 — 27 rows, vertebral larger. 

 Anal entire or divided. Subcaudals in two rows. Hab. Mexico to Brazil ; 

 Australia; Africa. 



(Himantodes.) 



Dipsas cenchoa. 



Coluber cenchoa Linne, 1758, Syst. Nat. Ed. X, 226. 

 Dipsas cenchoa Fitzinger, 1826, Ncue Class Rept., 59. 



Very long and slender, compressed, neck and tail very small; head 

 large, very broad, muzzle short, crown convex ; tail near one third of the 

 total. Eye large, pupil erect. Mouth deeply cleft, curved, Internasals 



