46 RANGE OF COLUBRINE SNAKES. [CH. I 



The Distribution of Snakes. 



The following account of the range of this order will 

 be limited to the Colubrine section, since Mr Boulenger's 

 catalogue, whence my information is derived, has not yet 

 reached the Vipers. The Colubrines, which are chiefly 

 though not entirely non-venomous serpents, may be divided 

 into seven families, the Typhlopidse, Glauconiidse, Boidse, 

 Ilysiidse, Uropeltidse, Xenopeltidse and Colubridse. Two 

 of these families, the Uropeltidse and Xenopeltidse, are 

 entirely confined to the Old World ; the former family 

 contains only seven genera of burrowing snakes which are 

 limited in range to Ceylon and other regions of India. 

 The Xenopeltida3 is a still smaller family, for it contains 

 only a single genus and species, which occurs in S. E. Asia. 

 The other families are more or less cosmopolitan. The 

 two largest of these are the Boidse and the Colubridae. 

 The Boidse are again subdivisible into two groups, the 

 true Boas and the Pythons. The latter are nearly entirely 

 Old World in habitat, the only exception being the Mexican 

 Loxocenius. On the other hand the Boinse are nearly as 

 exclusively American ; out of the thirteen genera which 

 Mr Boulenger allows in the sub-family six are purely 

 American, one belongs to the Australian region, one is 

 common to Asia and Africa, and two genera, Casarca and 

 Bolieria, consisting of a single species apiece are restricted 

 to Round Island near to Mauritius ; there remain the two 

 genera Corallus and Boa ; these are remarkable for the 

 fact that while both are almost entirely American or 

 Antillean in range they contain one or two species which 



