FRESH-WATER FISHES OF STAM, OR THAILAND 215 



and from the Chantabun and Krat Rivers in the Southeastern region. 

 From all of these waters specimens have been examined. 



A length in excess of 30 cm. is attained, but in Thailand examples 

 as large as 25 cm. are rare and the usual length of fully mature fish is 

 from 15 to 20 cm. 



The species is strikingly colored. In life the back may be rich 

 green, the sides creamy, the belly white,, with six to eight longitudinal 

 lines of black spots following the rows of scales, a spot on each scale, 

 the black lines sometimes extending to the ventral fins; the caudal, 

 anal, and ventral fins are red, the dorsal is pale yellow or red, and the 

 pectorals are white or greenish. 



Throughout its range this fish is esteemed as food, meeting with 

 ready sale at good prices. 



Several distinctive colloquial names are given to . hasselfu. In 

 most parts of Central Thailand, as well as in Southeastern Thailand, 

 it is known as pla soi khao^ in fancied resemblance to a dove {Strepto- 

 pelia) called nok khao, which has an area of small black and white 

 spots on each side of the neck; this name is frequently shortened to 

 2)la nok khao. Throughout Peninsular Thailand the name in common 

 use is pla khi khom {bitter-dregs fish), but in several places, as at the 

 J>ajo waterfall in Patani Province, the name pla tu l>o is applied; p7a 

 ill is the extremely abundant and commer(?ially important little mack- 

 erel of the Gulf of Siam, and ho is the bo tree, associated with the 

 Buddha. 



OSTEOCHILUS DUOSTIGMA Fowler 



Osteochilus duostigma- Fowler, 1937, p. 182, figs. 120, 121 (Keiuarat, Bangkok) ; 

 1939, p. 41 (Huey Yang). 



This species, described from the Meklong, with paratypes from the 

 Menam Chao Phya, resembles O. hasseltii in squamation, absence of 

 pores on snout, barbels, fins, large black spot on caudal peduncle, and 

 longitudinal lines of small spots following the rows of scales, and dif- 

 fers therefrom only in having a small cluster of black spots above 

 the pectoral fin, two spots being on the fourth scale of the lateral 

 line, and one spot on the scale above and one spot on the scale below 

 No descriptions of O. hasseltii refer to these spots. 



Four specimens 7 to 8 cm. long were caught with a dip net along 

 the bank of the Menam Chao Phya near Nakon Sawan, Central Thai- 

 land, January 5, 1925. In these the minute pearl organs, in addition 

 to thickly besetting the top of the head, occur on practically every 

 scale, even the most posterior scales on the caudal peduncle. The 

 round black spot on the caudal peduncle, larger than the eye, is sharply 

 defined, as are the black spots anteriorly on the lateral line and the 

 lines of dark spots following the rows of scales. 



A specimen, 9.2 cm. long, taken April 29, 1927, in Pliew waterfall 

 stream on Kao Sabap, Southeastern Thailand, agrees with the de- 



