FRESH-WATER FISHES OF SIAM, OR THAILAND 339 



Genus CERATOGLANIS Myers 



Ceratoglanis Myees, Copeia, No. 2, p. 98, 1938. (Type, Hemisihirua scleronema 

 Bleeker. ) 



Myers (1938) established this genus for the accommodation of a 

 species (scleronema) that for years had been carried in Hemisilurus. 

 The characters separating Ceratoglanis from Heniisilums are very 

 short, bony, hooked maxillary barbels (as opposed to long, filamentous 

 ones) and posterior nostrils situated before a vertical from the front 

 of the eye (as opposed to their position in or behind a vertical from 

 the front of the eye). 



CERATOGLANIS SCLERONEMA (Bleeker) 



hemisilurus scleronema Bleekek, 1862 (301), vol. 2, p. 93 (East Indies) ; Smith, 

 1931d, p. 181 (Nakon Nayok River). 



This fish was believed to be restricted to Borneo, Java, and Sumatra 

 until a specimen was taken in the Nakon Nayok River, Central Thai- 

 land, December 25, 1929. 



The specimen was 19 cm. long, but over twice that length is attained 

 in the Dutch East Indies. 



The local name of pla saiyu (hinge fish) was reported by the Boy 

 Scout who collected the unique specimen. 



Genus KRYPTOPTERUS Bleeker 



Kryptopterus Bleeker (189), Acta Soc. Sci. Indo-Neeii. (Siluri), vol. 4, pp. 21, 

 255, 283, 1858. (Type, Kryptopterus micropus {Bleekev ) =Silurus cryptop- 

 terus Bleeker.) 



With a single exception, the members of this genus in Thailand are 

 rather small. They are mostly inhabitants of the larger rivers, and 

 some of them occur in great abundance and enter conspicuously into 

 the food supply of urban and country people. The compressed body, 

 depressed head, rudimentary or absent dorsal fin, very long anal fin, 

 and two pairs of barbels render these fishes easily recognizable. There 

 are eight species assignable to the local fauna, as follows : 



la. Dorsal fin present but rudimentary (consisting of 1 or 2 rays) ; ventral rays 

 6 or 7. 

 2a. Maxillary barbels reaching end or posterior fourth of anal fin ; mandibulary 



barbels longer than head ; anal rays more than 70 linipok 



2&. Maxillary barbels not reaching beyond first fourth of anal fin ; mandibulary 

 barbels shorter than eye. 

 3a. Maxillary barbels reaching base of pectorals; branchiostegal rays 10 or 



11 ; anal rays 64 to 70 cryptopterus 



36. Maxillary barbels extending to ventrals or front of anal ; branchiostegal 

 rays 8 or 9; anal rays 52 to 70 bicirrhis 



