■380 



COLUBllIDJ^,. 



Fii?. 2G. 



Skull of Zamcnis gemoncnsis. 



Siinops'is of tJte Sjiecies. 



I. A pair of iiiternasals and a pair of praefrontals. 

 A. Posterior chin-shields in contact anteriorly *, 



Scales in 13 rows; ventrals 194-197 . 

 Scales in 15 rows; ventrals 1G2-177 . 

 Scales in 17 rows ; ventrals 190-208 . 



1. dipsas, p, 383. 



2. lorros, p. 384. 



3. iiiucosus, p. 385. 



B, Posterior chin-shields usually separated from each other by 

 scales. 



1. Scales in 15 or 17 rows (exceptionally 19 in Z. jiagelli- 

 formis ■?). 



a. Portion of rostral seen from above not more than half as 

 long as its distance from the frontal. 



a. Frontal anteriorly wider than the supraocular. 



* Scales in 15 rows ; fourth and fifth labials entering 

 the eye 4. oaxaca', p. 380. 



* It is necessary, for ascertaiiiiug this character, to distend the skin of the 

 chiu to make sure that small scales are not hidden in the iiieutal groo\e. 



