340 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



16. Dorsal fin absent ; ventral rays 8 to 10. 



4a. Vomerine teeth in a short, straight, elliptic band ; ventral rays 8. 



5a. Head 6.5 to 7.2 in standard length; lower jaw strongly projecting; anal 

 rays 74 to 83 ; base of anal fin 4.5 times length of head ; pectorals longer 



than head, the rays i, 16 or i, 17 hexapterus 



5&. Head 5.8 in standard length; jaws equal; anal rays 66; base of anal tin 

 3.5 times length of head; pectorals equal to head, the rays i, 13. 



nioorei 



46. Vomerine teeth in a curved or angular band; maxillary and mandibiilary 



barbels always shorter than head; pectoralti shorter than head; ventral 



rays 9 or 10. 



6rt. Vomerine teeth in an angular band; anal rays 78 to 91; nin.villary 



barbels reaching hind border of eye; mandibulary barbels sliorler 



than eye, sometimes absent; base of anal fin 8.25 to 3.5 times length 



of head apogon 



66. Vomerine teeth in a curved band; mandibulary barbels shoriei- than 

 eye, always present. 

 7a. Maxillary barbels reaching poisterior border of eye; anal ryys 86 to 



93; base of anal fin 4 times length of head micronema 



76. Maxillary barbels not extending beyond angle of mouth ; anal rays 

 about 80 ; base of anal fin 3 times length of head bleekeri 



KRYPTOPTERUS LIMPOK (Bleeker) 



Silurus Jimpok Bleekeb, 1S52 (67), p. 583 (Palembang, Sumatra). 

 Kryptopterm limpok. Smith, 1933a, p. 75 (Menam Chao Phya, Menam Sak). 



The Thailand records for this species, otherwise known only from 

 Borneo and Sumatra, are for three specimens taken in the Pasak River 

 at Dha Luang August 20, 1923, and one specimen caught with a cast net 

 in the Chao Phya River at Bangkok September 12, 1924 ; the specimens 

 are 16,5 to 19 cm. long. In one of the Pasak River specimens the max- 

 illary barbels extend to the end of the anal fin, in the others only to 

 the posterior fourth of that fin, wiiich seems to be usual; in two of 

 them the anal fin is clearly joined to the base of the caudal fin by mem- 

 brane. In all other characters the Thailand material is typical. 



KRYPTOPTERUS CRYPTOPTERUS (Bleeker) 



Silurus cryptopterus Bleekee, 1851 (35), p. 270 (Bandjermassing, Borneo). 

 Cryptopterus micropus GDnthek, 1864, vol. 5, p. 42 (Siam). — von Martens, 1876, 



p. 399 (Siam). 

 Cryptopterus cryptopterus Webeb and de Beia^xjfort, 1913, vol. 2, p. 218 (Siam). — 



HoEA, 1923b, p. 166 (Nontaburi).— ViPtnLYA, 1923, p. 225 (Bangkok). 

 Kryptopterus cryptopterus Fowlee, 1937, p. 136 (Paknam, Bangkok) ; 1939, p. 43 



(Krabi). 



The range of this species extends from Borneo and Sumatra to 

 Malaya and Thailand. It is one of the commonest of the kryptopterid 

 fishes in Thai waters, and it is known from the lower Chao Phya River, 

 the Pasak River, the Bangpakong River, the Meklong River, the Tapi 



