FRESH- WATER FISHES OF SIAM, OR THAILAND 417 



that a specimen, 25.2 cm. long, collected in the Bangkok market in May 

 1934 and described by Fowler as new under the name Hemipimelodus 

 hicolor is referred to this species. 



According to Fowler, H. hicolor may be known by its contrasted 

 coloration (not shown in the figure) and may be distinguished from 

 H. velutinus by having shorter barbels and an axillary pore. Not much 

 importance may usually be attached to the colors of market specimens 

 of fishes. In this case, the figure of H. velutinus in Weber and de Beau- 

 fort (1913, vol. 2, fig. 141) shows a much more striking contrast in color 

 than Fowler's figure. As regards length of barbels, this is often a 

 somewhat variable feature in catfishes, but Weber's description indi- 

 cates that the maxillary barbels extend "to base of pectorals or some- 

 what farther," while Fowler's figure indicates a maxillary barbel reach- 

 ing nearly the base of the pectoral. The presence of an axillary pore 

 in H. hicolor and its assumed absence in H. velutinus are important 

 points. Neither Weber in his original description nor Weber and de 

 Beaufort in their secondary description make any reference to an axil- 

 lary pore, although in the key to the species of Hemipimelodus occur- 

 ring in the Indo-Australian Archipelago, H. velutinus is placed in a 

 section characterized by the absence of an axillary pore. This, how- 

 ever, was an oversight. In a letter dated March 6, 1937, Dr. de Beau- 

 fort stated that he had just examined some typical specimens of velu- 

 tirms and found a small slitlike pore in all of them. 



For the present at least, the single Thailand specimen described by 

 Fowler as H. hicolor may be referred to H. velutinus. 



HEMIPIMELODUS SIAMENSIS Sauvage 



Hemipimelodus siamensis Sauvaoe, 1878b, p. 234 (Laos siamois) ; 1881, p. 162, 

 172, pi. 8, fig. 5 (Laos siamois; He de Phu-Quoc, Gulf of Siam).— Hoba, 1923b, 

 p. 170 (Nontaburl). 



The status of this species is uncertain. Sauvage's description is 

 deficient in diagnostic characters. His type, 20 cm. long, came from a 

 region where, in recent years, no hemipimelodid has been found or may 

 be expected to occur. His poor figure of the top of the head is not 

 suggestive. No statement is made as to depth of body, orbital margin, 

 teeth, gill rakers, axillary pore, relative position to adipose and anal 

 fins, and other features by which the fish might be distinguished from 

 other species. The description of the shape of the occipital process 

 with its strong keel applies well to horneensis and other species. If the 

 species is really valid, the most promising of the features mentioned by 

 Sauvage are the short maxillary barbels (extending to opercles), the 

 adipose fin almost as long as the dorsal and separated therefrom by 

 2.5 times its own length, the pectoral spine longer than the dorsal spine 

 and 16 rays in the anal fin, the only other species having so few rays 

 being H. velutinus. 



