352 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



of barbels (shorter in C. 'inacrocephalus) , and dorsal and anal rays 

 (fewer in C. rrmcrocephalus) . 



With the exception of G. hatrachus^ this is the commonest and com- 

 mercially the most important of the Thailand clariids. It is known as 

 pla duh uey {uey^ fat), and is rated higher than C. hatrachus^ its flesh 

 being richer, better flavored, and more nourishing, in popular opinion. 



Genus PROPHAGORUS H. M. Smith 



Prophagorus H. M. Smith, Copeia, 1939, No. 4, p. 236. (Type, Clarias nieuhofii 

 Cuvier and Valenciennes.) 



This genus was established to accommodate clariid fishes in which 

 the dorsal and anal fins are completely united with the caudal. The 

 name Phagorus (McClelland, 1845) is not available, having been based 

 on a mutilated specimen of Clarias hatrachus. Until recently only a 

 single species was known. A second species, described from Thailand, 

 is distinguishable by the characters given below : 



lo. Depth 8 to 9.3 in standard length ; dorsal rays 87 to 106 ; anal rays 69 to 95 ; 

 vomerine teeth in a crescentic band with a prominent median backward 

 extension nieuhofii 



lb. Depth 6.5 in standard length ; dorsal rays 67 ; anal rays 54 ; vomerine 

 teeth in a slightly curved elliptical band with no median backward exten- 

 sion cataractus 



PROPHAGORUS NIEUHOFII (Cuvier and Valenciennes) 



Clarias nieuhofii Cuyiek and V^vxenciennes, 1840, vol. 15, p. 386 (locality not 



given ) . 

 Phagorus nieuhofii Fowler, 1905, p. 461. 



Clarias nieuhofi Smith, 1934b, p. 288 (Nong Khor, Hoopbon, Krat River). 

 Prophagorus nieuhofi Smith, 1939b, p. 236 (new generic name). 



Although known from many islands in the Indo-Australian Archi- 

 pelago, as well as from the Philippines and Malacca, this species has 

 a very limited range in Thailand, being apparently restricted to 

 the southeastern district. The first known recognition of the fish lo- 

 cally was in November 1926, when a specimen 37 cm. long was taken 

 in Nong Khor; its body was marked by 13 transverse rows of white 

 spots equal to or larger than the eye, the side had an irregular longi- 

 tudinal band of large white spots, and the lower part of the body ex- 

 cept the belly was similarl}^ spotted; and the maxillary and mandi- 

 bulary barbels were longer than described by Bleeker and b}'^ Weber 

 and de Beaufort. The second specimen, taken in November 1931, 

 at Hoopbon in the same section was 36 cm. long and had all the bar- 

 bels greatly reduced in length, possibly by an accident. The only 

 other specimen, 13 cm. long, came from the Krat River near Kao 

 Seming, in December 1933. 



