THE STICKLEBACK 
HE sticklebacks are small fish, but 
they have the ferocity of sharks. 
The stickleback is well named, for 
along the ridge of his back are 
sharp, strong spines, five of them 
in our tiny brook species. These 
spines may be laid flat, or erected 
stiffly, and used to saw the scales 
off of his enemies. When we find 
the minnows in the aquarium los- 
efi} ing their scales, we may be sure they are 
y) being raked off by this sawback. 
i I have often kept in the aquarium several 
five-spined sticklebacks. This species is 
scarcely morethan 114 inches in length when 
fully grown. It is a slender, graceful fish, pointed 
like an arrow in front, and with the body behind 
the dorsal fin forming a long stem to support the 
rounded tail-fin. Its eyes are large and gem-like, 
and it has a wicked little mouth that opens upward. 
If in April we take the dip-net and go to some 
stagnant pond full of pond weed, we may be able 
to capture a stickleback guarding his nest; and by 
lifting carefully, and placing the contents of the net 
in water at once, we may be able to study this 
marvelous structure. It is built by the father 
stickleback, and we find the algae called frog- 
spittle is the building material. With this plant 
he builds a hollow sphere, about the size of a glass 
marble; he cements the walls with a water-proof 
glue, which he furnishes from his body. At one side 
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