Like others of his kind Sammy had a very strong spine in which was an
air-bladder. By pressing the air out of this he could swim easily at a
great depth, and by inflating it to let the air in, like a balloon, he
could rise and swim along the surface.

Sammy's eyes were large and round, and he could see splendidly,
especially when the water was clear. His hearing, as well as his sense
of smell was also good, and he breathed through the gills on each side
of his throat. When taken out of the water the fish really dies of
suffocation, for the water that enters its throat and flows out
through the gills is the air that keeps it alive.

Sammy's maiden aunt, an old fish who lived in the same stream with
him, used to tell strange tales of fish that can live several days out
of water by reason of the different formation of their gills.

One of these is a tropical fish called the Anabas. It has very strong
Pectoral fins which it uses like feet when on land, and it will even
climb trees to catch the insects which it eats.

Another fish of this sort is the Frog-Fish, a hideous creature which
is caught near Asia. It can crawl about a room, if shut up in one, and
looks exactly like an ugly frog.

But the most wonderful of all is a South American fish called the
Hassar. It usually lives in pools of water inland, and if the pool
where it is happens to dry up, it will travel a whole night over land
in search of a new home. It is an experienced traveler, and is said to
supply itself with water for its journey. If the Hassar finds all the