350 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



On July 12, 1928, the writer took two specimens, 11 and 15 cm. long, 

 from Klong Pong, at Ban Hue}?^ Ta, west of the town of Nakon Srita- 

 marat near the base of the lofty Kao Luang. 



The local vernacular name for the fish is 'pla mod. 



CLARIAS LEIACANTHUS Bleeker 



Chirim Uiacantlius Bleeker, 1851 (49), p. 430 (Sambas, Borneo) ; 1865 (347), 

 p. 35; 1865 (356), p. 175 (Siam).— Sauvage, 1881, p. 161 (Siam) (fide 

 Bleeker).— Smith, 1934b, p. 290 (attributed to Siam). 



This species is introduced into this catalog because it has been 

 attributed to Thailand by several authors. The evidence for its occur- 

 rence in that country will be considered. 



In two papers on Thailand fishes published in 1865, Bleeker listed 

 G. leiacanthus on the basis of a specimen or specimens in the Museum 

 du Jardin des Plantes in Paris collected from the Menam Chao Phya 

 by F. Bocourt, the species having been originally described by Bleeker 

 from Borneo in 1851, and is now recognized as inhabiting also Sumatra, 

 Bangka, and Nias. Until a few years ago, this species had not again 

 been reported from Thailand, all the intervening references in the 

 literature being based on Bleeker's papers. The natural conclusion 

 is that in the extensive collecting done in Thailand rivers in recent 

 years the fish escaped notice or that Bleeker made a mistake in 

 identification. 



In the writer's opinion the specimen or specimens from Thailand 

 that Bleeker in 1865 called C. leiacanthus were in reality G. mwxro- 

 cephalus, described from this country by Giinther in 1864. Bleeker 

 was apparently unfamiliar with the latter species which, with its 

 broadly curved occipital process and comparatively smooth pectoral 

 spine, might easily be mistaken for G. leiacantlms. 



In 1934 Fowler reported as taken at Bangkok two specimens of 

 Glai'ias leiacanthus., 210 and 217 mm. long. Mr. Fowler kindly allowed 

 the examination of one of these specimens. It differs from G. leiacan- 

 thus as described by Bleeker and by Weber and de Beaufort in the 

 position of the dorsal fin with reference to the occipital process, in- 

 the number of gill rakers, in the dorsal and anal fin rays, and in other 

 characters. The distance between the dorsal fin and the occipital 

 process is a feature diagnostic in the clariids. In G. leiacanthus this 

 distance is contained 2.5 times in the length of the head measured 

 along the median line, while in Fowler's specimen from Bangkok 

 this distance is contained over 7 times in the length of head. In 

 G. leiacanthus the gill rakers on the lower arm of the first arch number 

 13 (according to Weber and de Beaufort) ; in the specimen in hand 

 the number exceeds 25. The dorsal rays in G. leiacanthus are 76 to 78 



