152 
ZOOLOGY. 
ness, and is covered with round scales. The pectoral and 
ventral fins are long, narrow, and pointed, and tlie verte- 
bral column extends to the end of the caudal fin, which 
ends in a point, not being two-lobed as in other fishes. 
The Australian lung-fish (Fig. 195) has but a single lung, 
It attains a length of six feet. It can breathe either by 
gills or lungs alone. Ordinarily it uses its gills, but when 1 he 
Fig. 194.— Spoon-bill fish. From Liitken's Zoology. 
fish is compelled to live during droughts in thick muddy 
water charged with gases which are the product of decom- 
posing organic matter, it is obliged to use its lungs. It 
lives on the dead leaves of aquatic grasses, etc. The local 
Euglish name is ^^flat-head,^^ the native name being ^^bar- 
ramundi.^^ 
The African lung-fish (Fig. 196) has two lungs. It lives 
Fig. l^^.—Ceratodus, or Australian Lnn^-fish. (The tail in nature ends in a 
point.) 
on leaves in the White Nile, the Niger, and Gambia rivers, 
where it buries itself in the mud a foot deep. A similar 
lung-fish {Lepidosiren) lives in the rivers of Brazil, and 
the closely allied Protopterns in tropical Africa. Ceratodus 
makes use of the lungs mainly when the muddy water is 
saturated with gases from organic matter. 
Finally we come to those American Ganoids whose skele- 
