249 



CHAP. XVII. 



ARTICULATA, OR .JOINTED ANIMALS CIERIPEDA. 



" Curl-footed " Animals. Balanus or Acorn-shell. Barnacles. 

 Pentalismus anatifera. Popular Error. Young of the 

 Barnacle Shell, &c. 



PASSING from the numerous family of marine 

 worms which, as already stated, constitute the 

 class called the Annellata, we suppose the visitor 

 of the beach to proceed to examine the class 

 which naturalists have named Cirripeda (or curl- 

 footed). 



Examples of the Cirripeda may be found on 

 every sea-shore. The stones and rocks -covered at 

 high water, but left bare when the tide has ebbed, 

 are often found entirely covered with the most 

 common species. Shells which have been long 

 immersed in the water, limpets, oysters, whelks, 

 are also frequently found more or less occupied 

 by them. 



The animal now referred to is known as the 

 Balanus or acorn-shell. Our readers will easily 

 recognise it by a brief description. Each shell is 

 composed of several pieces, so placed together as 

 to form a cone, the broadest part of which is 

 attached to the rock or shell which forms its 

 abode. Of these acorn-shells there are several 

 varieties. The size of some is from about a 



