386 BULLETIN ISS, UNITED STATES NATIONAL MUSEUM 



There is some variation in the intensity, number, and position of 

 the dark longitudinal bands and also in the size of the adipose dorsal 

 fin, which is normally of about the same length as the anal base. A 

 specimen taken in a tributary of the Meklong near Rajaburi, charac- 

 terized by a very much longer adipose fin that extended nearly to 

 the dorsal, was submitted to Dr. Hora of the Indian Museum and pro- 

 nounced by him as within the limits of variation of the species as 

 observed in India. 



M. atrifasciatus Fowler, described from a number of specimens 11 

 to 11.8 cm. long (Fowler, 1937) and "distinguished from Mystus 

 vittatus chiefly by its much longer adipose fin," is believed by the 

 writer to be covered by the normal variation in this feature as well as 

 in the coloration in M. vittatus. 



The recording of Mystus tengara (Hamilton) from Thailand by 

 Bleeker and Karoli was probably erroneous. The matter was dis- 

 cussed by the writer in 1934 (b). No specimens referable to tengara 

 have been collected in Thailand in recent years. Regarding speci- 

 mens from Thailand in the British Museum that had been regarded 

 as M. tengara^ Mr. J. R. Norman wrote: "We have three specimens 

 from Bangkok (Fowler) and two larger ones labelled Siam (Prince 

 Champorn) in the British Museum as Macrones tengara. I have 

 examined these and find that they all agree with the description of 

 M. vittatus as given by Day. Thus, it appears that the true tengara 

 does not occur in Siam." 



The fish is usually called pla kayeng but sometimes is given the 

 distinguishing name of pla kayeng kang lai {kang lai, striped side). 



MYSTUS NEMURUS (Cuvier and Valenciennes) 



Bagrus nemurus Cuvier and Valenciennes, 1839, vol. 14, p. 423 (Java). 

 Hemihagrus nemurus Bleekek, 1865 (347), p. 34 (Siam) ; 1865 (356), p. 175 



(Siam).— Sauvage, 1883b, p. 154 (Siam). 

 Hemihagrus hoevenii Bleekeb, 1865 (356), p. 175 (Siam). 

 Macrones nemurus Weber and de Beaufort, 1913, vol. 2, p. 341 (Siam). — Hora, 



1923b, p. 171 (Nontaburi) ; 1924a, p. 468 (Tale Sap). 

 Mystus nemurus Fowler, 1934a, p. 95 (Chiengmai, Chiengsen) ; 1937, p. 148, 



figs. 44-47 (Bangkok, Pitsanulok, Tachin, Mepoon, Kemarat). 



Of wide distribution in the East Indies, this species occurs also on 

 the Asiatic mainland in Malaya, Indo-China, and Thailand. It is by 

 far the most numerous and most generally dispersed of the Thailand 

 members of the genus. It occurs throughout the Central district in the 

 Menam Nan, the Meping, the Mekok, and the Mekong in the Northern 

 area; in both branches of the Meklong, in headwaters of the Menam 

 Mun, in Peninsular Thailand in the Tapi River, the Tale Sap, the Tale 

 Noi, and the Patani River, in the Chantabun River, Southeastern re- 



