FRESH-WATER FISHES OF SIAM, OR THAILAND 47 



species are entitled to notice herein because at times they wander into 

 fresh water. They may be differentiated as follows : 



la. Caudal lobes with distinct black tips ; gill rakers on lower arm of first arch 

 38 to 44 melanura 



10. Caudal lobes without distinct black tips ; gill rakers on lower arm of first 

 arch 50 to 55 gibbosa 



SARDINELLA MELANURA (Cuvier) 



Clupea melanura Cctvier, 1829, p. 318 (locality not given). 



Of wide distribution in the East Indies and the Indian Ocean, this 

 species seems to be entitled to notice herein because of the existence in 

 the British Museum of a specimen from the Menam Chao Phya, a gift 

 from the old Siamese Museum. 



The species has been sadly confused with Harengula vlttata (q. v.) 

 and is variously called Harengula melanurus and Clupea {Harengula) 

 atri.cauda by Bleeker, Clupea atricauda by Giinther, Harengula com- 

 mersoni by Jordan and Scale, and Clupea {Harengula) atricauda by 

 Weber and de Beaufort. The writer follows Regan (1917, p. 384) in 

 identifying this fish with Clupea melanura Cuvier (1829) but not with 

 Alausa melanura Cuvier and Valenciennes (1847, vol. 20). From 

 Harengula vittata it may be distinguished by the generic characters 

 shown in the key and by the more posterior position of the ventral 

 fins, which are inserted under the middle of the dorsal in Tnelanura 

 and under or very slightly posterior to the origin of the dorsal in 

 mttata. In both forms the terminal part of each caudal lobe is 

 sharply marked off with black. 



SARDINELLA GIBBOSA (Bleeker) 



Clupea giMosa Bleekee, 1849 (10), p. (69), 72 (Macassar). 



Clupea (Harengula) fimbri-ata Webee and de Beaufokt, 1913, vol. 2, p. 75, figs. 26, 



27 (in part). 

 Sardinella gihhosa Regan, 1917, p. 383 (Siam). 



Although this is almost exclusively a marine species throughout its 

 wide range in the Indo-Australian Archipelago, in the Gulf of Siam, 

 and on the coasts of India and East Africa, in Thailand it has been 

 found in fresh water on a number of occasions. Specimens from the 

 Tapi River near Bandon, Peninsular Thailand, in September 1923, 

 were 9.5 to 10.5 cm. long. Five specimens from the Menam Chao Phya 

 at Paklat in February 1928 were 12.2 to 13.2 cm. long and all had large 

 isopods attached on the abdomen just behind the pectoral fins and on 

 the caudal peduncle, making ulcers. 



A length of 17 or 18 cm. is attained by this species. This species 

 occurs in abundance in the Gulf of Siam and is of great potential 

 value because of its suitability for canning as "sardines." 



The local vernacular name is pla lang keo (green-back fish). 



