10 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



The "Index," which is thus more than an index, serves the useful pur- 

 pose of giving a general list of the known species of Siamese fishes. 



During 12 years spent in Siam, the present writer published numer- 

 ous articles on the local fishes. These for the most part appeared in 

 the Natural History Supplement of the Journal of the Siam Society, 

 and one paper was contained in the Proceedings of the United States 

 National Museum under the title "Descriptions of New Genera and 

 Species of Siamese Fishes" (1931a), most of the species referred to 

 being from fresh water. Three articles on Siamese fresh-water fishes 

 of special popular interest — the walkingfish, the archerfish, and the 

 fightingfish — appeared in 1936 (a, b) and 1937 (b) in Natural His- 

 tory, the magazine of the American Museum of Natural History. Vari- 

 ous other papers, all listed in the accompanying literature cited and 

 dealing for the most part with matters of nomenclature, have been 

 published in Copeia, Proceedings of the Biological Society of Wash- 

 ington, Journal of the Washington Academy of Sciences, The 

 Aquarium, and elsewhere. 



ORIGIN AND RELATIONSHIPS OF THE FRESH- WATER FISH FAUNA 



In his earliest papers dealing with the fishes of Siam, Bleeker 

 (1859-60 [239] ) noted the strong resemblance existing between the fish 

 fauna of the Menam, the large river of Bangkok, and that of the rivers 

 of Borneo and Sumatra. He commented on the subject in a later 

 paper, about 1865, and noted not less than 35 species common to Siam 

 and to islands now separated from the mainland of Asia by wide and 

 deep stretches of salt water. Bleeker does not appear to have at- 

 tempted an explanation of this outstanding phenomenon. 



In a paper entitled "The Continental Shelf of French ludo-China 

 and the Relationship Which Formerly Existed between Indo-China 

 and the East Indies," Krempf and Chevey (1934), of the Oceano- 

 graphic Institute of Indo-China, announced the results of oceano- 

 graphic investigations and made deductions therefrom that bear on 

 the present similarity of the fish fauna of the East Indies and south- 

 eastern Asia. What was said of French Indo-China applies equally 

 well to Siam. They noted the work of Dutch investigators in studying 

 the continental plateau of Java and the Sunda Islands with reference 

 to its geological history and in tracing the course of river valleys now 

 submerged. In the southern part of the China Sea there has been 

 outlined a va^t estuary of a great river that drained northern Borneo 

 and Sumatra and the eastern slopes of the Malay Peninsula ; the bed of 

 this river, called the North Sunda River, is now under 40 to 100 meters 

 of water. Krempf and Chevey described the bed of a similar vast 

 river, called the Great South Indo-China River, which flowed from 

 northwest to southeast and emptied about 150 miles north of the North 



