22 3 



spine, which is not denticulated, scarcely or not longer than 

 postorbital part of head. Teeth in the jaws in a broad curved 

 band, those of the vomer in a very short elliptic band. 

 Length about 240 mm. [Type in Leyden Museum examined]. 



Nomen indig. : Lais puti (Mai. Banjerm.). 



Habitat: Java (Krawang) ; Borneo (Banjermassin); Sumatra 

 (Palembang). Siam. 



In fresh water. 



3. Fam. PLOTOSIDAE. 



Elongate, tail tapering. Head depressed. First dorsal fin 

 above or behind origin of pectorals, with a spine, which is 

 smooth, serrated on both edges or only along the hindborder. 

 No adipose fin, but a long or short so called second dorsal 

 or caudodorsal, probably a procurrent part of the caudal, 

 confluent with the caudal and often beginning with a fat 

 pad. Anal many-rayed, confluent with pointed caudal. Ven- 

 trals with 10 12 rays. Pectorals with a rather weak or 

 with a strong pungent denticulated spine. Nostrils remote 

 from each other, the anterior ones generally tubular, in the 

 frontborder of the upper lip and looking up or forward, or 

 perforating it and looking downward. Posterior nostril a slit 

 behind the nasal barbel. A pair of maxillary, mandibulary 

 and mental barbels; besides a lateral fold at the corner of 

 the mouth may be produced in a short barbel. Conical teeth 

 in the jaws, which may be wanting in the upper jaw and 

 mixed with molar-like ones in the lower jaw; on the vomer molar- 

 like or conical in a patch or band. Lateral line more or less 

 conspicuous by distant pores. Axillary porus present or absent. 

 A dendritic organ between anus and anal present or absent. 

 Gillmembranes united or more or less separated from each 

 other, totally or partly united with isthmus or free from it. 

 First branchial arch besides gillrakers, without or with a 

 membrane, the free edge of which is fringed or has rounded 

 processes, which may get independent. 



Key to the genera. 



I. A. praeanal dendritic organ. 



I. Anterior nostril perforating upperlip near its anterior 

 border and looking downward. Origin of second 



