Dules.—Body oblong, compressed, with scales of moderate size, and very indistinctly ctenoid. All the teeth are villiform; teeth on the vomer and palatine bones. One dorsal with ten spines; anal fin with three. Præoperculum serrated. Six branchiostegals only.
About ten species are known, inhabiting fresh waters of the coasts of the Indo-Pacific, and being especially common in the islands of this region, and also in Tropical Australia. Some live also in brackish water. Though of small size they are esteemed as food.
Therapon.—Body oblong, compressed, with scales of moderate size. All the teeth are villiform, those of the vomer and palatine bones being rudimentary, and frequently absent. One dorsal, with a depression in its upper margin, and twelve or thirteen spines; anal fin with three. Præoperculum serrated. Air-bladder with two divisions, an anterior and posterior. Six branchiostegals.
About twenty species are known, the distribution of which nearly coincides with Dules, but as some of the species are more or less marine, the genus is spread over the whole area of the tropical Indo-Pacific. Other species, especially those of Australian rivers, are entirely limited to fresh water. Th. theraps, Th. servus, and Th. cuvieri belong to the most common fishes of that area, extending from the east coast of Africa to Polynesia. They are readily recognised by the blackish longitudinal bands with which the body is ornamented. All the species are of small size. Helotes is closely allied to this genus.
Pristipoma.—Body oblong, compressed, with ctenoid scales of moderate size. Cleft of the mouth horizontal, not very wide, with the jaws nearly equal in length anteriorly; a central pit below the chin; villiform teeth in the jaws without canines; palate toothless. One dorsal, with eleven to fourteen spines; anal with three. Vertical fins not scaly, or with scales along the base only. Præoperculum serrated. Branchiostegals, seven.
Fig. 155.—Lower view of mandible of Pristipoma manadense.
About forty species are known, all from the sea. They are extremely common between the tropics, some of the species extending into the neighbouring sub-tropical parts. They do not attain a large size, and generally have a plain coloration. Conodon is an allied genus.
Fig. 156.—Hæmulon brevirostrum.