13. COLUBRID.^ 



len. Rostral plate very large, prominent, not very narrow, 

 often recurved between internasals on top of snout ; bounded 

 behind by internasal, anterior nasal, and first labial plates. 

 Plates on top of head are a pair of internasals, a variable 

 number of prefrontals (normally four), a frontal, supra- 

 ocular of each side, and a pair of parietals. Anterior and 

 posterior nasals usually distinct. Loreal usually elongate. 

 Preoculars usually one, occasionally two. Postoculars usually 

 three, often two. Supralabials usually eight, often nine. 

 Infralabials usually 13, often 12, sometimes 11 or 14. 

 Temporals of first row varying from two to five, usually 

 four. Genials in two pairs, anterior larger. Scales on body 

 in 27 to 33 rows, usually 29, keeled except in a varying 

 number of rows on each side. Anal plate not divided. Gas- 

 trosteges varying in number from 223 to 24-1, males having 

 from 227 to 241, females from 223 to 240. Urosteges in 

 two series of from 55 to 71, males having from 58 to 71, 

 females from 55 to 62. 



The ground color is pale brownish or grayish yellow, 

 sometimes more or less obscured by the spreading of the 

 blotches or the presence of black or dark brown marks along 

 the keels of its scales. Along the middle of the back, from 

 the head to a point over the anus, is a series of from 50 to 

 68 (average 58) dark blotches. These blotches are brown on 

 the central part of the body but are black anteriorly and 

 posteriorly. On the upper surface of the tail are from 14 

 to 20 (average 16.5) blackish blotches. On the anterior 

 portion of the body the blotches are more or less rounded, 

 but posteriorly they tend to become quadrate. There are 

 several series of alternating, often more or less confluent, 

 dark blotches or spots on the sides. Across the top of the 

 head, between the preocular plates, is a moderately narrow 

 brown band, very definite and well-defined. There are 

 similar bands or spots below the center of the eye and run- 



