A small freshwater-fish (Pantodon buchholzi), singularly alike to a Cyprinodont, from the west coast of Africa.
Twenty-first Family—Osteoglossidæ.
Body covered with large hard scales, composed of pieces like mosaic. Head scaleless; its integuments nearly entirely replaced by bone; lateral line composed of wide openings of the mucus-duct. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. The dorsal fin belongs to the caudal portion of the vertebral column, is opposite and very similar to the anal fin; both approximate to the rounded caudal (with which they are abnormally confluent). Gill-openings wide; pseudobranchiæ none; air-bladder simple or cellular. Stomach without coecal sac; pyloric appendages two.
Large freshwater-fishes of the tropics, whose singular geographical distribution has been noticed above (p. 223).
Osteoglossum.—Cleft of the mouth very wide, oblique, with the lower jaw prominent. A pair of barbels at the lower jaw. Abdomen trenchant. Bands of rasp-like teeth on the vomer, palatine and pterygoid bones, on the tongue and hyoid. Pectoral fins elongate.
O. bicirrhosum from Brazil and Guyana, O. formosum from Borneo and Sumatra, O. leichardti from Queensland.
Arapaima.—Cleft of the mouth wide, with the lower jaw prominent; barbels none. Abdomen rounded. Jaws with an outer series of small conical teeth; broad bands of rasp-like teeth on the vomer, palatines, pterygoids, sphenoid, os linguale, and hyoid. Pectoral fins of moderate length.
Fig. 299.—Arapaima gigas.
The largest freshwater Teleostean known, exceeding a length of 15 feet and a weight of 400 pounds. It is common in the large rivers of Brazil and the Guyanas, and esteemed as an article of food. When salted it is exported in large quantities from the inland fisheries to the seaports.