THE CRUSTACEANS SI 
the males are minute, degenerate creatures without shells, mouth or 
intestines, and live within the shell of the female. 

Fig. 48; Rock covered with Rock Barnacles. Cape Ann, Mass. 
The Rock Barnacle, (Balanus balanoides, Fig. 48S), is found 
along the Atlantic shores of Europe and America, from the Caro- 
linas northward. It lives only between 
tide levels, where it remains uncovered 
for a considerable period each half day, 
and is so abundant as to whiten the rocks. 
Individuals are crowded so closely to- 
gether as to become distorted and elon- 
gated in shape. When the tide is out 

the barnacles remain closed up, but as 
soon as the water reaches them the lids 2 
of the shells open, and the delicate curl- i: 
; Fig 49%; Deep-water Barnacle 
ing feet are thrust out at regular inter- growing upon a stone. From 
. . . life. Cape Ann, Mass. 
vals, sweeping food into the hungry eke wae 
mouths of the barnacles. At the least shock or jar the barnacles 
close their ids with a snap and the waving motion ceases. 
