THE MAILED WARRIORS OF THE SEA. 175 
Yet this is the true history of the barnacles and 
acorn barnacles of our coasts, and nothing can 
explain such extraordinary behaviour, except the 
overcrowding of the sea, and the struggle for life, 
which drove these curious creatures to prefer feeding 
upside down in places where others left room for 
them, to starving in an upright position. 
It is worth while to spend a short time sitting 
by a seaside pool or on the steps of a pier to watch 
the animals within the white shelly cones, called 
acorn-shells (Fig. 61, foreground), feeding in the sea- 
water. Each little cone is made of a number of 
shelly pieces, and in the middle of these you will see 
from time to time two valves (v) open, through which 
a tuft of feathery transparent fingers (<r) is thrust out, 
looking like a curl of delicate hair."" Then after 
opening out in the water, the curl is drawn up again 
just as you are beginning to admire it, and the valves 
close. Not for long, however, for almost imme- 
diately they open again and the same process is re- 
peated ; so that in a group of acorn barnacles all is 
in motion as one after another sweeps the sea for 
food. 
These tufts are in fact the fringed legs of the 
balanus, as the creature is called ; and looking at 
him as he is fastened down inside the shell, you will 
see that he is something like a rough attempt at a 
shrimp, lying on its back, mouth uppermost, so as to 
be able to seize and devour the minute creatures of 
the sea drawn in by the fringes of the legs. 
In this way safely ensconced in his jointed shelly 
carapace of carbonate of lime, it is easy to see that 
* These fingers are called cirrhi, from cirrhus, a curl or lock of hair. 
