2780 THE BONY FISHES AND GANOIDS 



these fishes "having hollow cavities in their heads, and an amphibious mode of 

 respiration, are able to exist for lengthened periods out of their native element, and 

 can travel some distance over the ground, especially when it is moist. They are 

 able to progress in a serpentine manner, chiefly by means of their pectoral and 

 caudal fins, first one of the former being advanced and then the other. These 

 fishes appear to be monogamous, some breeding in grassy swamps or the edges of 

 tanks, some in wells or stone-margined receptacles for water, and others again in 

 holes in river banks. The varieties which live in tanks and swamps keep much to 

 the shallow and grassy edges. Among the fish which I myself saw exhumed 

 from the mud of a dried-up tank were some Ophiocephali; they are also recorded 

 by the natives of India as descending with downpours of rain." When living in 

 muddy water they rise to the surface from time to time to take in atmospheric air, 

 and captive examples prevented from doing this have been known to die. During 

 the time they are buried in hard mud it must be assumed that these fish become 

 completely torpid and stop the respiratory function. 



THE LABYRINTH-GILLED FISHES Families ANABANTIDSE and LUCIOCEPH- 



ALID.& 



In the members of these two families of estuarine and fresh-water fishes, which 

 constitute a sectional group by themselves, the apparatus for enabling them to exist 

 for a considerable time out of the water is carried to a greater degree of complexity 

 than in the last, and? takes the form of a laminated accessory gill-like organ, situated in 

 a chamber on each side of the head above the one containing the true gills. In 

 these fishes the body is compressed, oblong, and elevated, with medium-sized ctenoid 

 scales. The eyes are lateral, the gills four in number, the gill opening rather nar- 

 row, and false gills either rudimentary or wanting. The single dorsal fin, as well 

 as the anal, has a variable number of spines; and the pelvic fins are thoracic in 

 position. While in some cases the lateral line is interrupted, in others it is altogether 

 wanting; and the air bladder may be either present or absent, but when developed 

 it is generally very large, sometimes even extending into the tail. These fishes, 

 which are of comparatively-small size, are confined to Southern Asia and South 

 Africa, and are all capable of existing for a longer or shorter period out of their 

 native element, when they oxygenate their blood directly from atmospheric air by 

 means of the accessory gill-like organ. Whereas some are carnivorous, others are 

 vegetable feeders; but all are capable of domestication, in which state they are sub- 

 ject to considerable variation, and several have been acclimatized in countries other 

 than their own. The flesh of all of them is said to be eatable, and that of some is 

 of excellent quality. On account of their brilliant coloration, and the curious 

 habits of some of them, these fish have always attracted more than ordinary interest. 

 The fish to which the somewhat inappropriate name of climbing 

 perch (Anabas scandens} has long been applied by Europeans in India 

 is the sole representative of a genus characterized by the presence of teeth on the 

 palate, and the serration of the free margins of the opercular and preorbital bones. 



