218 BULLETIN 18 8, UNITED STATES NATIONAL MUSEUM 

 OSTEOCHILUS MACROSEMION Fowler 



Osteochilus macrosemion Fowleb, 1935a, p. 116 (Srisawat). 



This species is regarded by Fowler as "apparently distinct" from 

 O. spilopleura, having no pores on the snout and a prolonged third 

 simple ray of the dorsal fin. "which Avhen depressed reaches nearly to 

 the end of the last branched ray. There is a tendency of the anterior 

 dorsal rays to become elongated in some large individuals of 0. 

 vittatits (Cuvier and Valenciennes), O. tHporii-s (Bleeker), and other 

 species of Osteochilus^ and this feature may have no specific im- 

 j)ortance. 



The type and only known specimen, from the Kwe Yai of tlie 

 Meklong at Srisawat in Central Thailand, is 18.5 cm, long, 



OSTEOCHILUS SPILOPLEURA Fowler 



Osteochilus spilopleura Fowlek, 193oa, p. 115, figs. 52, 58 (Srisawat). 



Only a single specimen of this fish was known at the time the species 

 was described; it was 21.3 cm. long and came from the ea.st branch of 

 the Meklong at Srisawat in Central Thailand. The species is char- 

 acterized by rostral barbels, large pores in two rows on the front of 

 the snout, entire lips, about 44 short gill rakers on the lower arm of 

 the first arch, and a black blotch at the fifth and sixth scales of the 

 lateral line extending partly above but mostly below the line. 



A specimen in hand 17.7 cm. long was collected by Phya Daruphan 

 Pithaks, chief conservator of forests, from the ]Mesoi, a tributary of 

 the Mewang, north of Lampang; it agrees fairly well with the descrip- 

 tion of the type. All the scales of the back and side have a dark basal 

 spot. The circumpeduncular scales, not mentioned in the original 

 description, number 20. 



The collector gave the local vernacular name for the fish as p7a 

 pik deng. 



OSTEOCHILUS PROSEMION Fowler 



Osteochilus prosemion Fowler, 1934a, p. 110, figs. 66, 67 (Chiengmai) ; 1937, 

 p. 1S3 (Kemarat). 



This fish is known from 4 specimens, 10.6 to 14.8 cm, long, from 

 the Meping at Chiengmai and the Mekong at Kemarat, 



Resemblance to O. spilopleura is seen in the presence of only rostral 

 barbels, 2 rows of large pores on the front of the snout, and a black 

 blotch across the lateral line above the pectoral fin. The principal 

 differences are entire instead of papillate lips, less numerous gill 

 rakers (about 30 as against 44), fewer predorsal scales, and 3 or 4 

 fewer branched rays in the dorsal fin. 



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