346 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



pet on July 30, 1929, has large ovaries containing clear, practically 

 ripe eggs. 



The fish is good to eat but fishermen do not like to handle it be- 

 cause of the painful wounds inflicted with its pectoral spines, which 

 are reputed to be very poisonous. 



For a century this fish was referred to in biological literature as 

 Saccohranchus fossilis Bleeker, although Heteropneiistes has priority 

 over SaccobrarwhiiS^ the name having been proposed by Miiller in 1839 

 for Silurus fossilis Bloch (1797), while "Valenciennes the next year 

 established Saccohranchus for Silwrus singio Hamilton (1822), singio 

 being a synonym of fossilis. 



A supposed new genus of Siluridae, Clarisihiru^, was described by 

 Fowler (1937), with C. kemratensis as the type, based on four speci- 

 mens, 14.3 to 21 cm. long, from the Mekong at Kemarat in Eastern 

 Thailand. The fish did not possess the characters diagnostic of the 

 Siluridae (such as subcutaneous eyes, gill membranes free from each 

 other and from the isthmus), and was clearly a Heteropn&ustes^ as 

 Myers (1938) indicated. The proper allocation was subsequently 

 made by Fowler (1939), who then expressed the view that the species 

 "appears to differ from H. fossilis (Bloch) chiefly in more anal rays 

 (75 to 84) ." No other features in which the fish differs from H. fossilis 

 have been indicated, and it seems altogether probable that H. hem- 

 Tatensis should be regarded as a synonym. The anal rays in H. fossilis 

 have been described as ranging from 60 to 79, thus overlapping those 

 in hem/ratensis. 



The name pla cheet is given to the fish in Thailand. It is not known 

 to the writer whether the English name sheat fish for the European 

 catfish Silurus glanis implies anything more than a coincidence. 



Family CLARIIDAE 



The clariid catfishes are of great interest because they have, in 

 addition to gills, an accessory breathing organ occupying the upper 

 part of each branchial cavity. These organs, having an arborescent 

 shape, enable the fish to breathe atmospheric air. The gills are rela- 

 tively small and appear inadequate to sustain life; fish that are pre- 

 vented from reaching the surface of a tank or aquarium soon die. 



The family is represented in Thailand by two closel}' lelated genera, 

 as follows: 



la. Dorsal, caudal, and aual fins entirely separated Clarias 



16. Dorsal, caudal, and anal fins united Prophagorus 



Much of the material used in the following account is taken from a 

 paper on clariid catfishes (Smith, 1934b). 



