FRESH-WATER FISHES OF SIAM, OR THAILAND 209 



February '24:, 1929. It is apparently very rare. The outstanding 

 characters are the deep, strongly compressed body ; narrow scooplikc 

 lower jaw with lip confined to the sides; absence of barbels; branchial 

 membranes broadly joined to the isthmus; pharyngeal teeth 5,3-3,5, 

 the first 4 teeth in the first row blunt, molarlike, the last being much 

 smaller and clavate, tlie teeth in the second row much smaller and 

 clavate; gill rakers very short, conical, 10+4 on first arch; long, high 

 dorsal fin with its last simple ray osseous and denticulated and its 

 branched rays numbering 14 ; and anal fin with 6 branched rays and 

 its last simple ray stout and osseous. 



Genus THYNNICHTHYS Bleeker 



Tliynnichthys Bueekee (261), Nat. Tijdschr. Neflerl.-Iiidie, vol. 20, p. 433, 1860. 

 (Tyi)e, LeucisGus thynnoides Bleeker.) 



THYNNICHTHYS THYNNOIDES (Bleeker) 



Leuciscus thynnoides Bleekek, 1852 (67), p. 599 (Palembang, Sumatra). 



Thynnichthys thynnoides Hoka, I923b, p. 154 (Nontaburi). 



Thynnichthys thai Fowlek, 1937, p. 177, figs. 114, 115 (Mepoon, Pitsanulok). 



In the East Indian Archipelago this fish appears to be confined 

 to Borneo and Sumatra. It is recorded also from Indo-China (Sau- 

 vage, 1881, p. 164) , and was to be expected in the Malay States where 

 Herre and Myers (1937) found it in Pahang and Perak. Its range 

 in Thailand covers the entire length of the country from north to 

 south. In the north, however, the fish is known only from the Mekok 

 at Chiengrai; that is, it seems to be absent from the Meping and its 

 tributaries. It has been taken in the Tale Sap, the Tale Noi, and the 

 Patani River in the Peninsula. It does not seem to be present in the 

 waters of Southeastern Thailand. At least, the collections therefrom 

 have failed to yield it. The fish seems rare in the Eastern area ; and 

 the collection contains a single specimen, 5 cm. long, taken from the 

 Menam Mun in November 1926. The great center of abundance is the 

 basin of the Menara Chao Phya. 



This fish may be recognized readily by its silvery sheen, minute 

 scales, deficient upper lip, and tumiylik^ shape. 



Adult fish are from 12 cm. long upward. A specimen with ripe 

 eggs, taken in the Patani River on October 15, 1923, was 15.5 cm. long. 

 The maximum size given by Weber and de Beaufort for Sumatra is 

 23 cm. The largest examples met with in Thailand were in a canal 

 in Bangkok; many collected with a cast net May 3, 1923, were 25 cm. 

 long. 



Many of the fresh-water fishes in the lower reaches of the coastal 

 rivers are very susceptible to a low degree of salinity of the water, 

 which comes at the end of the dry season, and this species is no excep- 

 tion. Fish in a small pond in Tonburi, Bangkok, connected with the 



