226 ON THE GEOGRAPHICAL 



Timor, by a slightly different system of colouring, and 

 thus form a constant variety, either local or climatal. 

 The Najas of the Sunda Isles constantly differ in several 

 characters from those of Bengal and of the Philippines. 

 The Ceratophrys of Sumatra forms a local variety or a race, 

 different from that of Java. The Serpents are not less 

 fertile in examples of this nature than the other orders of 

 Reptiles. We find that individuals of the Tortrix rufa of 

 Celebes are distinguislied from those of Bengal and of Java, 

 by a back of an uniform tint, and by two small spots on 

 the occiput. The Calamaria oligodon found at Java, pre- 

 sents, at Sumatra, a disposition of colours a little different 

 on the back, and forms, at Ceylon, and in the Philippines, 

 a third very handsome local variety. Analogous differences 

 exist between the Coronella Baliodeira of Java and Suma- 

 tra. The Lycodon Hebe of Java has a less size, and tints 

 a little different, and less bright, than those of Bengal ; the 

 specimens from Timor arc smaller than those of Java, and 

 have a deeper colour. The beautiful black-tailed snake, 

 Coluber melanurus, inhabits Java, Sumatra, and Celebes ; 

 but individuals from the latter have the nape constantly 

 ornamented by an angular black mark, while those of Su- 

 matra have the back rayed with black. The Ilerpetodryas 

 oxyceplialus is of a fine gi-ass-green in Java; this tint verges 

 on brown in specimens from Borneo, and those from Celebes 

 have all the upper parts of a very deep blackish-brown. 

 It mil suffice to say, that the Dendrophis picta inhabits 

 most of the intertropical countries of Asia, and from the 

 Senegal even to New Guinea, to enable us to guess how this 

 species must vary in countries so far distant from each other. 

 The Dryiophis nasuta, which usually comes from Bengal and 

 the jNIarianne Isles, has the belly streaked with yellow at 

 Java. The Dryiophis prasina, common m the Isles of the 

 Straits of Sunda, forms a local variety at Celebes ; the 

 Tropidonotus quincunciatus, which is one of the most vade- 

 ly spread serpents in India, shews at Java confluent spots, 

 so that the upper parts are streaked with black. The 

 Tropidonotus chryargos of Sumatra is distinguished from 

 that of Celebes, and both from that of Java ; and this dif- 

 ference, produced by a different arrangement of the colours, 



