SERPENT-HEADS. 
409 
and caudal fins, first one of the former beiim 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. Amongst 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. 
STRIATED SERPENT-HEAD (J liat. size). 
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,—F amilies Anabantidh: and Ltjciocebiialidje. 
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 narrow; 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 
