FRESH-WATER FISHES OF SIAM, OR THAILAND 441 



on the basis of the nostrils, whether one or two on the left side and 

 whether, if two, one of them is placed between the eyes or both are in 

 front of the lower eye. By far the larger number of species of the 

 genus frequent salt or brackish waters and are never found in fresh- 

 water streams. 



Fowder (1934a, 1935a, 1937) has credited to Bangkok and other com- 

 munities on the lower courses of rivers in Central Thailand many 

 strictly marine species of Gynoglossus^ of which specimens were simply 

 collected in the markets of those places. Among these species for 

 which the impression might be conveyed that they have a fresh- 

 water habitat are C. arel (Bloch), hilineatus (Lacepede), honieensis 

 (Bleeker), cynoglossus^ macrolepidotus (Bleeker), monoj)us (Bleek- 

 er), puncticeps (Richards), and semifasciatus (Day). The only 

 species that are known to frequent fresh water regularly are those 

 herein listed. 



All the fishes of this genus bear the vernacular name of pla lin ma 

 (dog-tongue fish) in Thailand. It is noteworthy that this name is an 

 exact translation of the Greek generic name. 



la. No lateral line on blind side ; scales in lateral line 126 to 135 ; tip 

 of rostral hook not extending beyond vertical from front margin 

 of upper eye xiplioideus 



1&. A lateral line on blind side; scales in lateral line 132 to 150; tip 

 of rostral hook reaching behind vertical from posterior margin of 

 lower eye microlepis 



CYNOGLOSSUS XIPHOIDEUS Gunther 



Cynoglossus aiphoideus GtJNTHEE, 1862, vol. 4, p. 495 (Siam) ; 1864, p. 179 (Siam 

 and Cambodia).— Bleeker, 1865 (347), p. 33 (Siam); 1865 (356), p. 173 

 (Siam). — HoEA, 1923b, p. 182 (Nontaburi). — Weber and db Beaxifort, 1929, 

 vol. 5, p. 193 (Siam).— Smith, 1933a, p. 83 (Menam Chao Phya). 



Collections made in Thailand by the celebrated traveler Mouhot 

 contained the specimens on which this species was based by Giinther 

 in 1862. The fish has since been found to be fairly numerous in the 

 Menam Chao Phya as far upstream as Ayuthia, and may often be seen 

 in the river markets, where it has some reputation as a food fish. 



Examples over 20 cm. are common. The largest observed, taken 

 at Koh Yai March 16, 1928, was 28 cm. long. 



The original description of the species gave a single lateral line on 

 the blind side, but none of the specimens examined in Thailand had any 

 such lateral line, and according to information received from J. R. 

 Norman the type material in the British Museum lacks a lateral line 

 on the blind side. 



A specimen 22.5 cm. long from Koh Yai had no upper eye, its posi- 

 tion being represented simply by a socket, from which it was impossible 



