13. COLUBRIDJE 



Description. — Head somewhat flat-topped or rounded 

 with snout projecting and rather narrow. Temporal regions 

 not swollen. Rostral plate very large, prominent not very 

 narrow but 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, supraocular of each side, and a pair of parie- 

 tals. Anterior and posterior nasals usually distinct, some- 

 times united. Loreal usually elongate. One or usually two 

 preoculars; and three or four, usually three, postoculars. 

 Tips of some labials may be cut off forming suboculars or 

 loreals. Supralabials usually eight, sometimes nine or 10. 

 Infralabials usually 13, sometimes 12 or 14. Temporals of 

 first row varying from two to six, usually four. Genials 

 in two pairs, anterior much larger than posterior. Scales on 

 body in 29 to 37 rows, usually 32) or 31, keeled except in a 

 varying number of rows on each side. Anal plate not di- 

 vided. Gastrosteges varying in number from 223 to 263, 

 males having from 224 to 252, females from 223 to 263. 

 Urosteges in two series of from 50 to 72, males having 

 from 58 to 72, females from 50 to 67. 



The ground color is pale yellow or grayish yellow, some • 

 times more or less obscured by the spreading of the blotches 

 or the presence of dark keels on the scales, especially later- 

 ally and anteriorly. Along the middle of the back, from 

 the head to a point over the anus, is a series of from 46 to 

 66 (average 5S) dark brown blotches. These blotches may 

 be blackish or actually black on the neck and toward the 

 tail, and may be more or less margined with black through- 

 out. On the upper surface of the tail are from 12 to 21 

 (average 1 5.4) dark brown or black blotches or cross-bars. 

 The dorsal blotches on the anterior part of the body may 

 be rounded, but they soon become more or less quadrate 



