synopses and descriptions. 85 



Cheilorhina. 

 Shape and general appearance that of Elapomorphus, from which it is 

 distinguished by the greater number of rows of scales, and by the smooth 

 teeth, which gradually increase in size backward. 



Cheilorhina villarsii. 



(Be Fil.) Jan, 1862, Prodr. Icon. Ophid., pp. 55 and 57; Icon. Livr., 48, pi. I, fig. 5. 



Head not distinct from the neck; tail short, thick, blunt; snout prom- 

 inent, broad, rounded. Internasals united with the prefrontals. Frontal 

 hexangular, anterior angle produced. Supraciliaries short, broad. Nasals 

 entire, united with the anterior labials. Loreal present. Preocular one. 

 One postocular. One temporal, in contact with the ocular. Five labials, 

 including that united with the nasal, third "below eye and orbitals. Infra- 

 labials six. Submentals one pair. Scales broad, smooth, in 19 rows. 

 Ventrals 213. Anal entire. Subcaudals 15 pairs. 



Crown, labials, and infralabials black to the temporals. With trans- 

 verse rings of black, more or less incomplete below, separated by spaces 

 of about half their width. The first black ring crosses the neck, and occu- 

 pies about seven scales. Two rings surround the tail; all grow narrower 

 on the flank. Western Mexico. 



Stenorhina. 



Burnetii & Bibron, 1854, Erp. Gen. VII, 865. 



Moderate, subcylindrical, belly flattened; head little larger than the 

 neck, depressed, narrow forward; tail short, stout, conical. Eye small to 

 moderate, pupil round. Posterior maxillary teeth a little longer, grooved. 

 Internasals and nasals usually fused. Nasals divided. No loreal. Scales 

 smooth, in 17 rows. Generally one ante and two post oculars. Anal bifid. 

 Subcaudals in two rows. Mexico to Central America. 

 Uniform brownish or slightly blotched ; 



bases of scales darker fremenvillei. 



with longitudinal bands of darker, quinquelineatus. 



Stenorhina fremenvillei. 



Burnetii & Bibron, 1854, Erp. Gen. VII, 868. 



Cylindrical, belly broad, tapering slightly to neck and tail ; head mod- 

 erate, little, if any, larger than the neck, depressed, crown flattened, 

 slightly arched in front of the eye ; tail short, stout, conical. Eye small, 



