410 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 

 TACHYSURUS TRUNCATUS (Cuvier and Valenciennes) 



Arius truncatus Cuvier and Valenciennes, 1840, vol. 15, p. 64 (Java). — Bleeker, 

 1865 (356), p. 175 (Siam).— von Martens, 1876, p. 400 (Bangkok).— Sauv age, 

 1881, p. 162 (Siam).— Weber and de Beauiort, 1913, vol. 2, p. 308 (Siam). 



Cephalocassis truncatus Bleeker, 1859-60 (239), p. 102 (Siam). 



Tachysiirus truncatus Fowler, 1934a, p. 93 (Bangkok). 



? Eemipimelodus cochlearis Fowler, 1935a, p. 101, fig. 25 (Bangkok, Paknam). 



An abundant, strongly marked species of Java, Sumatra, and west- 

 ern side of the Malay Peninsula, this fish in Thailand is found mostly 

 in the lower courses of the larger rivers, and at times may occur in 

 large numbers. From all the other members of the genus in Thailand, 

 it may be readily distinguished by its much-depressed head, truncate 

 snout, and greenish yellow color, often rich creamy yellow below. 



The maximum length given for this species by Bleeker is 33 cm. 

 The average for a dozen adult specimens chosen at random in the 

 collection of the Siamese Bureau of Fisheries was 31 cm., the largest 

 being a female of 42 cm. with nearly ripe eggs, taken in the Tale Sap 

 on July 9, 1929. 



Fowler's Hemipimelodus cochlearis bears a strong resemblance to 

 this species. It is described and figured as having a small patch of 

 teeth on each palatine, thus excluding it from the genus Eemipime- 

 lodus. 



The vernacular names differ somewhat with the locality. In the 

 Menam Chao Phya the fish is known as pla uh lueng. In the Bang- 

 pakong, the next large stream to the eastward, the same name, to- 

 gether with pla hot lao {lao, spear), is in use, while in the Meklong, 

 the large stream entering the northwest corner of the Gulf of Siam, 

 the fishermen call this fish pla hot hua lao {hua lao^ spear head) . Still 

 another name is in general use in the inner lake of the Tale Sap, where 

 this fish is abundant and known as pla han lao {lean lao, spear handle) . 



TACHYSURUS MACRONOTACANTHUS (Bleeker) 



Arius macronotacanthus Bleeker, 1846 (3), p. 150 (Batavia). — Hoka, 1924a, p. 

 468 (Singora). 



This species is known from the Straits Settlements, Sumatra, and 

 Java. Its place in the Thailand fauna rests on a single young speci- 

 men reported by Hora from Singora. 



TACHYSURUS CAELATUS (Cuvier and Valenciennes) 



Figure 91 



Arius caclatus Cuvier and Valenciennes, 1840, vol. 15, p. 66 (Batavia). — Weeee 



and DB Beaufort, 1913, vol. 2, p. 310 (Siam).— Karoli, 1882, p. 178 (Siam). 

 Ceplialocassis coelatus Bleeker, 1859-60 (239), p. 102 (Siam). 

 Arius coelatus Bleeker, 1865 (356), p. 175 (Siam). 

 Tachysurus caelatus Fowler, 1935a, p. 100 (Bangkok, Paknam). 



One of the common fishes of the genus, this species is found along all 

 the shores of the Gulf of Siam, in the Tale Sap, and in the tidal reaches 



