220 OPHIDIA. 



a dark spot below the eye ; belly yellowish, with quadrangular brown spots, irregularly 

 arranged and more numerous posteriorly than anteriorly. 



Dumeril and Bibron say that their specimen is from China. Our specimen (type of Cantor's 

 Xenodon purpurascens) is from Pinang, and agrees almost entirely with Dumeril's description : 

 but it has three postoculars instead of two ; the lower prseocular is much smaller than the 

 upper, which, again, is sometimes divided into two ; temporals rather irregularly arranged. 

 Our specimen is 24 inches long, the tail measuring of inches. 



FAMILY OF COhV^mYyY.^—COLUBRIDJE. 



This family comprises the greater part of tlie non-venomous snakes, 

 namely all those which do not present any striking character either In their 

 general habit, In the shields of the head, In the dentition, or In any other 

 part of their organization : we therefore describe the body as of moderate 

 length compared with Its circumference, flexible in every single part ; the 

 head as well-proportioned In every dimension, and distinct from neck ; the 

 eye of moderate size, the nostril lateral ; the cleft of the mouth in accord- 

 ance with the length of the head. They have numerous teeth in the jaws 

 and on the palate, but no fangs in front or In the middle of the maxillary. 

 The subcaudals are two-rowed ; and the chin-shields symmetrically arranged, 

 separated by a longitudinal mental groove. 



These snakes are found in every part of the temperate and tropical regions, but are only 

 scantily represented in Australia and in the islands of the Pacific. The species are so 

 numerous and show such a gradual passage between extreme forms, that, although genera 

 can be easily characterized, it is almost impossible to distinguish wider groups by definite 

 characters. We have endeavoured to refer the genera to certain groups distinguished by 

 their mode of life ; but in order to determine a species it is sufficient to compare only the 

 generic characters without reference to those given for the groups. 



Synopsis of the Genera. 

 GROUP OF GROUND COLUBRIDES— (76)i2(9iVEii/iY4. 



Colubride snakes of small size, with smooth scales, which generally are disposed in thirteen, 

 fifteen, or seventeen series ; some of them approach in general habit the Calamandie, whilst 

 others have a more slender body and even angulated ventral shields. They live on the 



