116 Beautiful Shells. 



closed in a fine skin or mantle. The mouth is 

 placed at the lower part, near the opening, whence 

 the cirrhi issue forth ; this mouth is a curious piece 

 of mechanism, being furnished with a horny lip 

 covered with minute palpi, or feelers; there are 

 three pairs of mandibles, that is jaws, the two outer 

 ones being horny and serrated, that is jagged or 

 toothed like a saw; the inner one is soft and 

 membranous, that is, composed of little fibres, like 

 strings, crossing each other, as we see what are 

 called the veins in a leaf. 



Much more might be said about the internal 

 structure of the Cirrhopods, or Balani, as the 

 Barnacle group is sometimes called, from the Latin 

 Balanus — a kind of acorn. By some naturalists, 

 the term is not applied to the stalked Girrhipoda, 

 like that we have been describing, but only to the 

 sessile kinds, that is, those which set close or grow 

 low ; from the same Latin root comes the English 

 word session — a settling. The coverings of these 

 Dwarf Barnacles are sometimes called acorn shells; 

 they are commonly white, of an irregular cone 

 shape, composed of several ribbed pieces, closely 

 fitted together with an opening at the top, closed 

 by an operculum, or stopper. 



These shells cover in patches the surface of 



