FRESH-WATER FISHES OF SIAM, OR THAILAND 369 



The usual vernacular name for this fish is pla sangkawad^ some- 

 times modified to pla sangkaioad leuang. 



PANGASIUS LONGIBARBIS Fowler 

 Pangasius longibarbis Fowler, 1934a, p. 87, fig. 27 (Chiengsen). 



Described from 2 specimens, 12 and 5.6 cm. long, taken in the Mekong 

 at Chiengsen, Northern Thailand, in February 1933, this species is 

 known from no other locality but may, of course, be looked for along 

 adjacent stretches of the Mekong. Its most salient features are the 

 length of the maxillary barbels, which reach beyond the origin of the 

 anal fin, and the long anal fin, which has 39 to 41 branched rays. The 

 vomero-palatine teeth, which in this genus are so important for spe- 

 cific identification, are undescribed as to shape and relations of bands. 

 There are said to be "narrow villiform bands on vomer," and there is 

 no mention of palatine teeth. The position of the species is therefore 

 uncertain, but as the describer states that it is related to Pangasius 

 siamensis it has been provisionally placed in the foregoing key in the 

 section characterized by vomero-palatine teeth in 4 separate patches. 



Genus PTEROPANGASIUS Fowler 



Pteropangasius Fowlek, Proc. Acad. Nat. Sci. Philadelphia, vol. 89, p. 142, 1937. 

 (Type, Pangasius cultratus H. M. Smith.) 



PTEROPANGASIUS CULTRATUS (H. M. Smith) 



Pangasius cultratus Smith, 1931a, p. 25 (Peninsular and Central Siam). 

 Pteropangasius cultratus Fowlek, 1937, p. 144, figs. 31-33 (Mepoou) ; 1939, p. 43 

 (Krabi). 



The type and paratype of this species came from the Tapi River 

 near Bandon, Peninsular Thailand, in September 1923. Additional 

 specimens available at the time the species was described were from 

 the Sikuk and Chao Phya Rivers, Central Thailand, in November 1923, 

 and September 1924. The fish was next observed in August 1930, 

 when one was collected in the Meklong, at Rajaburi, Central region. 

 Seven specimens from Mepoon, Central district, in 1936 are referred 

 to by Fowler. 



The type, 26 cm. long, is the largest example obtained. 



In view of the possession of a median keel extending the entire 

 length of the abdominal cavity, combined with greatly compressed 

 body, short maxillary barbels, and very numerous anal rays, this 

 specimen has been made the type of a new genus, Pferopangasms, by 

 Fowler. It may be pointed out that the description and figure of the 

 dentition given by Fowler do not agree with that of the type and 

 paratype in the U. S. National Museum as regards the vomeropalatine 

 teeth. The original description indicated two horizontal ovate patches 

 of vomerine teeth with an oblique patch of palatine teeth on each side, 



