INTRODUCTION. XXIU 



is specifically distinct from that which is so prevalent in Pegu, viz., T. elongata. 

 The affinity, however, manifested by the northern species, T.platynota, is more towards 

 T. actinodes than to T. elongata ; and it is a remarkable circumstance that, whilst 

 T. plafynota does not extend either into Assam or into Bengal, T. elongata is found 

 on the outskirts of the eastern border of the plateau of Central India, and would also 

 appear to exist in the Terai region of the Sikkim-Himalaya. 



But certain reptiles, which are highly characteristic of the Indian fauna, are 

 also found at Bhamo, viz., Calotes versicolor, Tropidonotus stolatus, and Passerita 

 mycterizans, associated with such Indo-Malayan forms as Calotes mystaceus, the first 

 and the last occurring together also at Mandalay. In the Kakhyen hills, and 

 in the country beyond, T. stolatus is supplanted by T. dipsas, a Himalo- Chinese 

 species. 



In the Kakhyen hills, that Malayan type Draco is found, but rarely ; while in 

 the valleys to the east, the fauna is characterized by such forms as Pseudopus, which 

 also occurs in Lower Pegu, the Khasia hills and the Sikkim-Himalaya, and others, 

 e. g., Japalura, Oriocalotes, Ablabes, Coluber, Elaphis, which are essentially Hima- 

 layan forms ; and with these is associated the Malayan type Ophites. Even the indi- 

 vidual species of these genera are either identical with, or are very closely allied to, the 

 species occurring in the Eastern Himalayas, while the Trimeresurus of the high 

 valleys of Western Yunnan is identical with T. monticola. 



Occurring along with these Ophidian forms in the area to the east of the 

 Kakhyen hills, and chiefly to the east of Muangla, are fou.nd the Palgeartic types 

 Tylototriton, and Carassius as represented by the gold carp ; and it is especially 

 worthy of note that all of these forms, with the exception of Carassius, are also dis- 

 tinctive of the fauna of the Sikkim-Himalaya. 



The sudden transition from the valley of the Irawady to the high country of 

 Yunnan is very striking, because the traveller, after three marches over the Kakhyen 

 mountains, is suddenly introduced from a Burmese-speaking population, clad in the 

 light, many-coloured flimsy garments of a tropical people, into a Chinese-speaking 

 race, clothed in the thick, dull-blue habiliments of a mountain people. This change 

 of scene, however, is not more marked than that which distinguishes the faunae and 

 florae. After the dense vegetation and Burmese fauna of the valley of the Irawady 

 are left behind, and the Burmo-Himalayan flora and mixed Burmese Indo-Malayan 

 and Himalayan fauna of the Kakhyen hills have been passed, the elevated country 

 becomes bare and grassy, and Burmese and Malayo-Himalayan species give way 

 before others which are essentiaUy Chinese and Palaeartic. The j)hysical features, 

 however, of these regions have, as I have already said, been described in detail in my 

 previous works on the scientific results of the two Expeditions to Western Yunnan. 



