416 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



lected also in both the upper and the lower reaches of the Menam Bang- 

 pakong. A specimen, 18.5 cm. long, taken in June 1923 in the Menam 

 Chao Phya at Pakret, a short distance north of Bangkok, was com- 

 pared, in December 1927, with Bleeker's type of H. horneensis, 17.6 

 cm. long, in the British Museum and found to agree perfectly. 



The maximum length in local waters somewhat exceeds 25 cm. Fully 

 mature specimens of both sexes are found from 15 cm. upward. 



Figure 93. — Hemipimelodus horneensis (Bleeker). Drawn by Nai Chote Suvatti; 

 courtesy of the Thailand Government. 



The ovaries develop bilaterally, and in conjunction therewith a 

 peculiar pad forms on the inner side of each ventral fin, as in Tachy- 

 surus. There is no modification of the ventral fins in the male. The 

 fully mature ovaries occupy so large a part of the abdominal cavity 

 that the passage of food along the intestines is interfered with or 

 altogether stopped by. the time the large, clear, amber-colored eggs 

 are ready for extrusion. Some ripe fish taken in a haul seine March 29, 

 1928, were 15.6 to 22.1 cm. long, had dull reddish gray back and sides, 

 and showed a glistening white spot, smaller than the pupil, in the 

 median cranial fontanel. 



The fish is caught in considerable quantities with seines, bag nets, 

 and other apparatus, and appears regularly in the markets of the larger 

 river towns. 



The common vernacular name is pla uk, in allusion to the grunting 

 noise the fish makes when caught. Qualifying terms are added in 

 certain localities or for certain color or other peculiarities, such as 

 pla uh deng (deng, red), pla uk khao {khao, white), and pla uk khem 

 {khem, needle). A name heard only on the Bangpakong River is 

 pla kot poh^ kot being equivalent to uk and poh being the kind of trap 

 in which caught. 



• HEMIPIMELODUS VELUTINUS Weber 



Hemipimelodus velutinus Webee, 1908, p. 225 (New Guinea). 

 Hemipimelodus Mcolor Fowlee, 1935a, p. 100, fig. 23 (Bangkok). 



Hemipimelodus velutinus has heretofore been known only from 

 northern New Guinea. It is therefore with considerable hesitation 



