CAT-FISHES. 569 



spine. Singiilarly, two species (P. platychir and P. halayi), 

 are found in West Africa. The majority are of but moderate 

 size and plain coloration. — Allied South American genera (also 

 ■without teeth on the palate), are Pirinampus, Conorhynchus, 

 Notoglanis, Callophysus, Zophiosilurus. 



AuCHENOGLANis. — Adipose fin rather long, dorsal short, with 

 a pungent spine and seven rays ; anal short. Snout produced, 

 pointed, with narrow mouth. Barbels six, none of which belongs 

 to either of the nostrils, which are remote from each other. The 

 teeth of each jaw form a pair of small elliptic patches which are 

 longer than broad ; palate edentulous. Eyes of moderate size. 

 Ventrals sis-rayed. 



One species, Au. hiscutaius, from the ISTile, Senegal, and 

 other West African rivers. 



d. Aeiina. 



Arius.— Adipose fin of moderate length or short ; a short 

 dorsal fin with a pungent spine and seven soft rays ; anal fin 

 rather short. Head osseous above ; barbels six, four at the 

 mandible, none at either of the nostrils which are close together. 

 Eyes with a free orbital margin. Caudal fin forked j ventrals 

 six-rayed, behind the dorsal. 



Of all Siluroid genera this has the greatest number of 

 species (about seventy), and the widest distribution, being 

 represented in almost all tropical countries which are drained 

 by large rivers ; some of the species prefer brackish to fresh 

 water, and a few enter the sea, but keep near to the coast. 

 Some of. the species are of small size, whilst others exceed a 

 length of five feet. The extent of the armature of the neck 

 and the dentition vary much in the different species, and 

 affords two of the principal characters by which the species 

 are separated. — The following genera are allied to Arius, 

 Galeichthys from South Africa ; Genidens and Paradiplomystax 

 from Brazil ; Biplomystax from Chile ; Aelurichtkys from 

 Central and South America ; Jlemipimelodus, Ketervgus, Osteo- 



