FRESH-WATER FISHES OF SIAM, OR THAILAND 347 



Genus CLARIAS Scopoli 



Chlarias Scopoli, Introductio ad historiam naturalem, p. 445, 1777. (Type, Clarias 

 orontis Giinthier,) 



The catfishes of this genus are among the most abundant, most widely 

 distributed, and most important economically of the fresh-water fishes 

 of Thailand. They are eaten extensively in the households of fisher- 

 men and farmers, and are regularlj^ offered for sale in the markets of 

 Bangkok and other communities throughout the country. Fish are 

 exposed for sale alive in baskets, in shallow tubs with little or no 

 water, or on stone slabs, like Anabas and Ophicephalus, and if not sold 

 one day they are taken back to market the next day. The fish have 

 a great reputation for their wholesome qualities, and are in special 

 demand for convalescents and invalids. 



The name Clarias, first used for these fishes by Gronow in 1763, lost 

 its status as a valid generic name of that author and date with the 

 rendering of the Opinion (No. 89) of the International Commission on 

 Zoological Nomenclature that the systematic names of Gronow are 

 declared eliminated from consideration. This name, like a number of 

 others brought out by Gronow, was validated by Scopoli in 1777, and 

 although credited to Gronow by Scopoli was spelled Chlarias. Four 

 other fish names of Gronow validated by Scopoli and credited by him 

 to Gronow were given a different spelling; these were Holocenthrus 

 for Holocentrus^ Gonovynchus for Gonovhynchus, Golichthys for Cal- 

 lichthys, and Mastocemhelus for Mastacerribelus. It cannot be stated 

 whether the variant orthography of Scopoli was due to deliberate in- 

 tent, to carelessness, or to tj^pographical error, but inasmuch as Scopoli 

 definitely recognized Gronow as the authority, it seems proper in the 

 case of Clarias, as has been generally done in all the other cases, to 

 adhere to the original spelling. 



Five species of Clarias have been ascribed to Thailand but only three 

 species can be definitely accredited on the information now available. 

 The five species are differentiated as follows : 



Iff. Pectoral spine with strong, sharp, prominent teeth on its anterior border. 



meladerma 



1&. Pectoral spine without prominent teeth on its anterior border, which is 



smooth, rough, or inconspicuously denticulated. 



2fl. Occipital process more or less angular with rounded tip, its basal width 



about 2 times its length in medium-sized fish. 



So. Distance from dorsal fin to occipital process contained 4 to 5.5 times in 



length of head measured along upper median line; dorsal rays 60 to 



76 ; anal rays 47 to 58 batrachus 



3&. Distance from dorsal fin to occipital process contained 2.5 times in length 

 of head measured along upper median line ; dorsal rays 70 to 74 ; anal 

 rays 60 to 63 tevsmanni 



