142 BULLETIN 114, UNITED STATES NATIONAL MUSEUM. 



Polyzona may be distinguished from annulata and from nelsoni 

 by the presence of black tips on the red scales; by the snout, which 

 usually has a transverse light band in polyzona, is entirely black in 

 annulata, and is mottled with dark and light in nelsoni. From 

 micropTiolis it may be known by the white cross band on the snout 

 instead of the white snout with black transverse marks, and by 

 the fact that the yellow annuli are narrow, and their scales plain 

 pT more or less mottled with black as well as black-tipped, instead 

 of being wide with the scales heavily tipped with black and not 

 mottled, and by the presence of two anterior temporals instead of 

 usually only a single large one. 



The dental characters are as follows: Maxillary teeth, 13 to 15, 

 usually 14, subequal except that the last 2 or 3 are distinctly, although 

 not strongly, enlarged; mandibulars, 13 to 15, commonly 14, the 

 third, fourth, and fifth or the fourth, fifth, and sixth, decidedly the 

 largest, those posterior much smaller and decreasing slightly in 

 size; palatines, 10 to 12, commonly 10, subequal; pterygoids smaller, 

 decreasing, varying from 16 to 22. 



The penial characters, as indicated by preserved specimens, are 

 as follows: Sulcus single; a small space at the distal end without 

 calyces or with only ridges across it; immediately adjacent to this 

 a few calyces with only a very few fringes; succeeding calyces with 

 numerous fringes, gradually changing to spines; latter closely set 

 together, numerous and slender, increasing in size to about the 

 middle of the organ, then rapidly decreasing to very small spines, 

 and disappearing altogether; basal third of organ smooth (or ridged 

 or ribbed in preserved specimens); no spines distinctly enlarged 

 or set apart from the others. 



Habitat and Jiahits. — Sumichrast (1880, 181) says ^'Cette espece 

 vit dans les terres chaudes et temperees des deux cotes du Mexique. 

 Sa coloration, analogue a celles des Elaps, la fait injustement accuser 

 de venin par les habitants qui Fappellent corallilo." 



Cope (1900, 900) quotes, as from the manuscript notes of Sumi- 

 chrast, as follows : 



Among the numerous Mexican snakes which are called "coralillas, " this one 

 attains the largest dimensions. It is distributed throughout the warm and temper- 

 ate regions, but disappears in the alpine region, where, at least, I have never observed 

 it. This snake prefers shaded localities, as plains covered with talj herbs, and along 

 rivers. Although of a very harmless disposition, it is not easily caught, since on 

 being alarmed it glides swiftly through the vegetation and is not long in disappearing 

 in the gallery excavated by some other animal. It also lives in the enormous nests 

 of the ant, Orcodoma mexicana, on which it warms itself in the sun. Although entirely 

 inoffensive, it does not escape the charge of being poisonous, as all the coralillas are 

 supposed to be by the natives. 



