418 BULLETIN 188, UNITED STATES NATIONAL MUSEUM 



A specimen, 15 cm. long, from the Menam Cliao Pliya above Bangkok 

 was identified by Hora as belonging to this species, but he did not give 

 differential features. 



Family AKYSIDAE 



This family is represented in Thailand by a single genus, Ahysis. 

 Regan, Jordan, and others have placed the genus in the family 

 Amblycipitidae (Amblycepidae) with Amblyceps; Fowler (1934a) 

 put Akysis in the Bagridae. The present writer follows Weber and 

 de Beaufort (1913, vol. 2) and Hora (1936a) in assigning Akysis to 

 a separate family to include Acrochordonichthys (Java and Sumatra) 

 and Breitensteinia (Borneo and Sumatra). The differential char- 

 acters given in the key to the families of Nematognathi, together with 

 others that might be indicated, seem to warrant the maintenance of 

 this as a distinct family. 



Genus AKYSIS Bleeker 



Akysis Bleeker (189), Act. Soc. Sci. Indo-Neerl. (Siluri), vol. 4, p. 234, 1S5S. 

 (Type, Akysis variegatus (Bleeker) — Pimelodus variegatus Bleeker.) 



The members of this genus are diminutive inhabitants of mountain 

 streams in Java, Borneo, Sumatra, Burma, and Thailand. Four 

 species have been ascribed to Thailand and another {A. pictus Gim- 

 ther) , described from Tenasserim, may be looked for in the adjoining 

 parts of Thailand. The known species from Thailand may be char- 

 acterized as follows : 



la. Nasal barbel as loug as, or longer than, head ; maxillary barbels 1.2 to 1.25 

 times length of head ; all fins and barbels speckled with brown or 



black maculipinnis 



1&. Nasal barbel shorter than head. 



2a. 7 to 10 antrorse denticles on posterior edge of pectoral spine; length of 



caudal peduncle twice or less than twice its depth. 



3a. 7 to 9 very strong teeth on pectoral spine as long as or longer than breadth 



of spine; nasal barbel reaching branchial opening; maxillary barbel 



extending to second third of pectoral spine ; dark red, with longitudinal 



rows of yellow spots on head and transverse rows of yellow spots on 



body armatus 



3&. 10 moderately developed teeth on pectoral spine; nasal barbels not 

 reaching branchial opening; maxillary barbel not reaching base of 

 pectoral spine; body mostly whitish, with 3 irregular black cross 



bands, snout white leucorhynchus 



26. 4 or 5 denticles on posterior edge of pectoral spine; length of caudal 

 peduncle 3 times its depth or more macronem^us 



AKYSIS MACULIPINNIS Fowler 



Akysis maculipinnis Fowt^kr, 1934a, p. 97, flg. 46 (Southeastern Siam). 



Known only from seven specimens 3.1 to 3.7 cm. long, from Chanta- 

 bun, Southeastern Thailand, presumably from a tributary of the 

 Chantabun Kiver. 



