FRESH-WATER FISHES OF SIAM, OR THAILAND 



405 



Figure 90. — Bairachocephalus mino (Hamilton). Drawn by Nai Chote Suvatti; 

 courtesy of the Thailand Government. 



terior edges. The development of barbels is less than in any other 

 local catfish, being restricted to a minute pair on the chin. 



Genus OSTEOGENEIOSUS Bleeker 



Osteogeneiosus BlEeker (3), Nat. Geneesk. Arch. Ned.-Ind., ser. 2, vol. 3, pp. 146, 

 173, 1846. (Type, Osteogeneiosus macrocephalus Bleeker.) 



OSTEOGENEIOSUS MILITARIS (Linnaeus) 



Sil'urus militaris Linnaeus, Syst. Nat., ed. 10, p. 305, 1758 (Asia). 



Ranging from Java, Borneo, and Sumatra to India, this species is 

 one of the commonest catfi&hes around the shores of the Gulf of Siam, 

 in the lower courses of rivers, and in the inner lake of the Tale Sap. 

 It may at once be identified by the single pair of stiff, semiosseous 

 barbels that arise on the snout and extend to or beyond the base of the 

 pectorals. 



A length of 30 cm. is reached in Thailand. 



Oral incubation is practiced in this species. The egg-laying and 

 egg-hatching season appears to be prolonged and may extend over the 

 entire year. Thus, males 18 to 23 cm. long collected on July 2, 1923, in 

 the Bangpakong Eiver 8 miles from the Gulf of Siam, in fresh water 

 with a strong current, had mouthfuls of eggs in various shapes of 

 development; females collected in Bandon Bight, Gulf of Siam, on 

 September 21, 1923, had well-developed eggs, some 1 cm. in diameter; a 

 male taken in the Tale Sap on October 6, 1923, had in the mouth 12 

 undeveloped eggs of a rich yellow color ; a female, 30 cm. long, taken 

 in the Gulf of Siam at Pakpoon, Nakon Sritamarat, October 20, 1923, 

 contained large ovarian eggs; and females 25 and 25.5 cm. long, col- 

 lected from a trap in the Gulf of Siam off the mouth of Menam Cliao 



590087—45- 



-27 



