118 THE HALL OP SHELLS, 



" In their first form these little castle hold- 

 ers, but dancing atoms, have one big black eye, 

 three pairs of legs, and on the forehead a pair 

 of flexible horns. If we did not know the end 

 we should say a mistake had been made in 

 their legs, which seem to grow more and more 

 unfit for use either for land or water. 'As- 

 cending the scale,' the body with its fringed 

 legs, to which are added two pair more, is now 

 inclosed in a tiny two-valved shell like a mus- 

 sel. Its one eye becomes two, its head and 

 antennae increase in size, and it now prepares 

 to make the most wonderful change of all. It 

 ' stands on its head' literally and fastens itself 

 head downward to the rocks by means of a 

 cement itself secretes. Its bivalve shell is no 

 longer needed, its shield becomes the beginning 

 of its castle walls, and its group of legs become 

 tentacles which wave gracefully backward and 

 look like delicate curls of hair. It is these 

 which give the name Cirripeda to this group, 

 cirrus meaning a lock of hair andj9e^es a foot. 

 ' " They now are true barnacles, and their 

 castles by the sea are like turrets crowding one 

 upon another. 



"All barnacles are not the same kind, and 

 their turrets are not all upon the rocks. Many 

 are attached to pieces of wood, hulls of ships, 



