A'NABAS (from avaeatvw, to ascend), the name given by Cuvier to a genus of Acanthopterygious Osseous Fishes, remarkable for the power possessed by the species of living for some time out of water, and making their way on land. This power depends on a structure characteristic of the family of which it is the type, part of the pharangeals being labyrinthiform; that is to say, divided into a number of irregular lamella:, more or less numerous, forming cavities and little cella capable of retaining a certain quantity of water. This apparatus is so protected, that when the animals are out of their native element the evaporation of the contained water takes place very slowly, and the gills are kept moist, by means of which remark able provision the fishes of this family are enabled to leave the rivers and marshes where they usually reside, and to travel over land for considerable distances, creeping among the herbage or along the ground. this fact has been but recently known to modern naturalists, the ancients appear to have been well acquainted with it, and Theophrastus has recorded the existence in India of certain little fishes which leave the rivers for a time, and again return to them : he doubtless alludes to the Anabas and its allies.
The genus A nabas, of which there is but one species, the A nabas scandens scandena of Daldorf, Anthias testudineus of Bloch), is distinguished by a well-marked character, the borders of its operele, aubopercle, and interopercle being denticulated, whilst the preopercle is not so, nor even distinctly marginated. The head is round and broad ; the muzzle is very short and obtuse, the eye placed very near its extremity. The mouth ie small, and large scales cover the head. The body is oblong, compressed centrally and behind. The lateral line is interrupted at its posterior third, recommencing a little lower. The tail is somewhat rounded. The whole body is covered with large
scales. There is a single dorsal and an anal fin, nearly equal in height, and in both the spinous rays prevail.
In colour it appears to vary, being brown or bluish-black or dark green, paler beneath and having violet fins. In form the individuals are constant, and reach the length of G inches.
This fish inhabits all parts of India and the Indian Archipelago, living in marshes and feeding on aquatic insects, and Dr. Cantor observed it at Chusan. Respecting its habits there has been much discussion. In 1797 a Danish gentleman, M. Daldorf, communicated an account of its habits to the Linnman Society of London, in which he stated that he had observed it in the act of ascending palm-trees near marshes, and had taken it at a height of no less than 5 feet above the surface of the water, effecting its movements of ascent by means of its fins and tail and the spines of its opercles, in a similar manner to that by which it progressed along the ground. Another Danish observer, M. John, published a similar statement, adding that it is called in Tranquebar by a name which signifies Tree-Climber. Other naturalists, who have equally observed it in its native countries, such as Reinwardt, Leschenault, and Hamilton Buchanan, whilst they record its habit of creeping on the ground and living a long time out of water, deny or omit all mention of its power to ascend trees.
To the same family with Anabas belong the genera Helostorna, Polyacanthus, Colisa, Macropodus, Osphromenws, Trichopus, and Spiro branchas, of which the habits are as yet very imperfectly known, though the peculiarities of their anatomy warrant us in supposing that they have a similar power of living out of water.
(Linneean Transactions, vol. ill.; and Cuvier and Valenciennes, Hist. Nat. des Poissons, toni. vii)