i 7 6 
LIFE AND HER CHILDREN. 
Fig. 62. 
the balanus lives more securely than if he had re- 
mained a freely roving creature as we see him at 
i, Fig. 62 ; and the 
success of his re- 
tirement to a fixed 
life is proved by the 
countless number of 
acorn - shells which 
are found on every 
sea-shore. The Icpas 
or barnacle with 
stalks (Fig. 61), you 
will see less often, 
for they live in deeper 
water attached to 
rocks or pieces of 
[~~1> floating timber. 
Their history is the 
same as that of the 
v 
Development of an Acorn Barnacle. acom-shell,Only that 
1, A young acorn barnacle before it ^ rom tne cement of 
has settled down. Spence Bate. their antennae they 
2, The grown-up acorn barnacle cut in form j fl h 
naif; , head cemented to the shell; a, J 
back ; m, position of the mouth ; c, cirrhi Stalks which fasten 
fringing the legs which sweep in the food ; j-} ie head to its SUO- 
r, valves of the shell. Darwin, 
port. 
And here we must take leave of the Crustacea. 
We have really only made acquaintance with three 
branches; 1st, the ten-footed and stalk-eyed crus- 
taceans, the prawns, and crabs ; 2d, those with eyes 
fixed in the shell and breathing-gills fixed to the legs, 
the sandhoppers, and skeleton shrimps ; and 3d, the 
barnacles. But these by no means represent even 
