354 
serrations. Base of adipose fin equal to that of the dorsal, 
the distance between them is twice that length. Pectoral spine 
strongly denticulated posteriorly and less so anteriorly, twice 
as long as the dorsal one. Ventrals not reaching anal, their 
origin immediately behind the vertical through end of base 
of dorsal. Origin of anal before vertical through origin of 
adipose fin. Caudal deeply bifurcate. Least height of caudal 
peduncle 1°/, times in its length. The bands of teeth in the 
jaws and on the palate are equally narrow. Blackish brown, 
lighter below. A light cross band from nape downward and 
lighter patches on the sides behind dorsal and adipose fin. 
‘Dorsal with a dark submarginal band. Adipose fin blackish 
with a light hindborder. Other fins lighter with dark bands 
or patches. Length of single specimen known 51 mm. (Type 
in Leyden Museum seen by us). 
Nomen indig.: Baung Bebang. 
Habitat: Borneo (Upper Mahakam river!). 
2. Leiocassis mahakamensis Vaill. 
Leiocassis mahakamensis Vaillant, Notes Leyden Mus. XXIV. (n°. 1—3), 1902, p. 55. 
1D: iw OGoaAss 162 Pe. 1: 73 We0G: 
Head depressed, covered by soft skin. Height 6, head 37/5, 
eye about 8, shorter than the short, obtuse snout, slightly 
prominent, the length of which is equal to the interorbital 
space and ?/, of the length of the head. Occipital process 
short, pointed, triangular, certainly not reaching the basal 
bone of the dorsal spine. Barbels rather long, the nasal barbels 
nearly reaching end of head, the maxillary ones nearly reaching 
to the extremity of the pectoral spine, mandibulary barbels 
reaching on pectorals, mental ones shorter. Dorsal spine short, 
*/, of the length of the head. Adipose fin '/, longer than the 
dorsal, the distance between both longer than the adipose fin. 
Caudal deeply forked, especially the upper lobe prolonged. 
Anal beginning opposite to adipose fin. Pectoral spine strong, 
strongly denticulated at both edges, about equal to head 
without snout. Ventrals far behind end of dorsal, about equal 
to postorbital part of head. Palatine teeth in a semicircular 
band. Upper surface of head and body bluish black, ventral 
surface white, with a rufous hue, along each side a narrow 
whitish band, running from behind the opercle to base of 
