Subclass Dipneusti, or Lung-fishes 241 
They are known in Queensland as Barramunda. They inhabit the 
rivers known as Burnett, Dawson, and Mary, reaching a length 
of six feet, and being locally much valued as food. From the 
salmon-colored flesh, they are known to the settlers in Queens- 
land as ‘“‘salmon.” According to Dr. Gunther, ‘the Barra- 
munda is said to be in the habit of going on land, or at least 
on mud-flats; and this assertion appears to be borne out by 
the fact that it is provided with a lung. However, it is much 
more probable that it rises now and then to the surface of the 
water in order to fill its lung with air, and then descends again 
until the air is so much deoxygenized as to render a renewal 
of it necessary. It is also said to make a grunting noise which 
may be heard at night for some distance. This noise is proba- 
bly produced by the passage of the air through the cesophagus 
when it is expelled for the purpose of renewal. As the Barra- 
munda has perfectly developed gills besides the lung, we can 
hardly doubt that, when it is in water of normal composition 
and sufficiently pure to yield the necessary supply of oxygen, 
these organs are sufficient for the purpose of breathing, and 
that the respiratory function rests with them alone. But 
when the fish is compelled to sojourn in thick muddy water 
charged with gases, which are the 
products of decomposing organic 
matter (and this must be the case 
very frequently during the droughts 
which annually exhaust the creeks 
of tropical Australia), it commences 
to breathe air with its lung in the 
way indicated above. Ifthe medium 
in which it happens to be is perfectly 
unfit for breathing, the gills cease to 
have any function; if only in a less 
degree, the gills may still continue 
to assist in respiration. The Barra- 
munda, in fact, can breathe by either 
P 
: z Fig. 175.—Upper jaw of Neocera- 
gills or lung alone or by both simul-  wodus forsteri Ginther. (After 
taneously. It is not probable that “el 
it lives freely out of water, its limbs being much too flexible 
for supporting the heavy and unwieldy body and too feeble 
