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 six-rayed.
One species, Au. biscutatus, from the Nile, Senegal, and other West African rivers.
d. Ariina.
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; 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; Diplomystax from Chile; Aelurichthys from Central and South America; Hemipimelodus, Ketengus, Osteogeniosus, and Batrachocephalus from the East Indies; and Atopochilus from West Africa.
Fig. 261.—Arius australis, from Queensland.
e. Bagariina.
Bagarius.—Adipose fin rather short; a short dorsal with one spine and six rays; anal fin of moderate length. Barbels eight, of which one pair stands between the anterior and posterior nostrils which are close together. Head naked above. Caudal fin deeply forked; ventrals rays six. Thorax without longitudinal plaits of the skin.
A large Siluroid (B. bagarius) from rivers of India and Java; exceeding a length of six feet.