FRESH-WATER FISHES OF SIAM, OR THAILAND 379 



and Perak; and Leiocassis micropogon (Bleeker), of Sumatra and 

 Borneo, is recorded from Malacca. Both of these species may be found 

 eventually in Peninsular Siam. 

 The three species from Thailand may be differentiated as follows : 



la. Depth of body 3.75 to 4.25 in standard length ; barbels relatively short, the 



maxillary reaching to or beyond posterior edge of eyes but not to gill 



openings. 



2a. Head long, its width about 0.6 its length ; dark brown cross bands with 



light interspaces; a continuous submarginal black or dark cross band 



on caudal fin poecilopterus 



2b. Head shorter, its width about 0.8 its length; dark brown or black cross 

 bands with white interspaces; each caudal lobe with or without a 



black subterminal spot siamensis 



16. Depth of body 4.6 to 6 in standard length ; barbels long, the maxillary and 

 mandibulary reaching beyond base of i)ectorals ; head short, its width about 

 0.8 its length ; light brown, with irregular dark markings stenomus 



LEIOCASSIS POECILOPTERUS (Cuvier and Valenciennes) 



Bagrus poecilopterus Cm-iEE and Valenciennes, 1839, vol. 14, p. 431 (Java). 



Liocassis poecilopterus Petebs, 1868, p. 272 (Siam). 



Leiocassis poecilopterus Webee and de Beaufort, 1913, vol. 2, p. 356 (Siam). 



The assignment of this species to Thailand is made on the authority 

 of Peters. No examples have recently been met with, although there 

 is no reason why the jfish may not occur in local waters, as do numerous 

 other species known otherwise from Java, Borneo, and Sumatra. 



LEIOCASSIS SIAMENSIS Regan 



Figuee 83 



Liocassis siamensis Regan, 1913, p. 550 (Bangpakong River) ; Hora, 1923b, p. 172 



(Menam Chao Phya at Noutaburi). 

 iLeiocassis bicolor Fowler, 1934a, p. 95, fig. 43 (Chiengmai, Bua Yai). 

 ILeiocassis alUcollaris Fowlee, 1934b, p. 337, fig. 2 (Bangkok) ; 1937, p. 150, figs. 



54-63 (Bangkok, Pitsanulok, Mepoon). 

 Leiocassis alHcollis Fowler, 1939, p. 58 (Trang). 



This fish is common and widely distributed in Thailand. It has been 

 collected by the present writer in the Menam Chao Phya at numerous 

 places throughout its course to its head at Paknampo and in many 

 collateral streams (Chao Chet, Sikuk, and others), in the Mewang 

 at Lampang, in the Meklong at Rajaburi and Potaram, in the Menam 

 Mun at Pakjong and Ta Chang, in the Menam Tapi and the Menam 

 Tadi in Peninsular Thailand, and in brackish Avater of the Chantabun 

 River. In January 1926 I obtained specimens at Kompong Chnang, 

 on an outlet of Tonle Sap, the great inland sea of Cambodia. 



The Deignan collection contains specimens obtained in April and 

 June 1935 in the Meping at Chiengmai and in the Meklian and Mechem, 

 tributaries of the Meping. 



