388 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



Ayuthia, presented by the Siamese Museum many years ago, and on 

 the recent records by Fowler of numerous specimens, the largest 28 cm. 

 long, from Central, Peninsular, and Southeastern Thailand. The fish 

 is known also from Java, Borneo, Sumatra, Malacca, and Perak. 



MYSTUS WYCKII (Bleeker) 



Bagrus imjckii Bi^eekek, 1858 (189a), p. 156 (Java). 



Mystus wi/cki Smith, 1929, p. 12 (Meyom). 



Mystus tvycJcii Fowleb, 1935a, p. 104, fig. 31 (Bangkok). 



The first Thai record for this species, previously known only from 

 rivers of Sumatra and Java, was published in 1929 and was based on 

 a specimen 40.4 cm. long, obtained from the Meyom, north of Lampang, 

 in Northern Thailand, by Phya Daruphan Pithaks, chief conservator 

 of forests. Several specimens had been taken for the Siamese Bureau 

 of Fisheries in earlier years : One in the upper Menam Chao Phya, No- 

 vember 26, 1923 ; one in the Lopburi River at Lopburi, Central Thai- 

 land, October 22, 1926; two in the east branch of the Kanburi River, 

 Central Thailand, September 10 and 12, 1928. A fish found in the 

 Bangkok market September 11, 1929, had come from Lante, on the 

 Menam Chao Phya, and another in that market November 19, 1929, 

 had been caught at Koh Yai, on the same river. In the Deignan col- 

 lection are one specimen 15 cm. long from the Meping at Chiengmai, 

 and another obtained by A. R. Buchanan, from the Mechem, a tribu- 

 tary of the Meping, at a point about 50 miles above its mouth. 



The largest example met with was 48 cm. long, which is probably 

 near the maximum length attained. 



The species may be recognized easily by its very broad, flat head 

 with smooth upper surface and upward-directed eyes, the dark violet 

 back and sides, the white underparts, whitish areas on the upper side 

 of the orbit, in the interorbital space, and on the posterior margin of 

 the opercle, with a sharply defined creamy yellow edge on the upper 

 and lower borders of the caudal fin and on the anterior edge of the 

 anal and ventral fins. There is considerable variation in the length of 

 the barbels, depending doubtless on age. Normally the maxillary bar- 

 bels reach to the dorsal fin or even close to the adipose, but in a speci- 

 men from the Kanburi River these barbels extend beyond the base of 

 the anal fin, while the mandibulary barbels, which usually reach no 

 farther than the branchial openings, in this specimen reach to the tip 

 of the pectorals. 



The vernacular name given the fish at its first-mentioned Thai lo- 

 cality was pla kot hang mor (pot-sided catfish) . Among the fishermen 

 in the Bangkok region this rare fish is known as ;;>?« hot hao (crystal 

 catfish). 



