PIERCED SHELLS AND CHITONS 253 



sea-worms creep away as fast as possible, the poor 

 mollusks can only cling to the rock for protection, 

 or curl themselves up into the smallest space and 

 the most secure condition which their instinct can 

 dictate. 



When you visit the seaside you will want to ex- 

 amine all these harmless little inhabitants of the 

 ocean, and among them you will probably early dis- 

 cover some specimens of our next group of mollusks, 

 the Chitons, or sea-cradles, as they are sometimes 

 called. The anatomy of these animals is similar to 

 that of the limpets, but they seem less highly de- 

 veloped, and are probably descended from a very 

 ancient race. They are peculiarly sluggish crea- 

 tures, and they live in cracks and crannies of the 

 rock or else under stones, away from all scenes of 

 activity. 



But the peculiar feature that distinguishes them 

 is the fact that the shell of the Chiton consists of 

 eight parts, instead of a single shield. These parts, 

 or valves, run across the body and overlap one an- 

 other, like shingles on a roof. They are highest in 

 the center, and they end in a leathern mantle which 

 runs around the body, and which is highly con- 

 tractile. This being the case, their shells cannot 

 be preserved with the same ease as those of the lim- 

 pets, for the mantle must be dried while the valves 

 are in their natural position. 



Probably the best way to prepare line specimens is 

 to bind the living animal upon a piece of shingle or 

 lath as it rests extended in a pan of sea-water. It 

 can then be placed in warm fresh water, and after 



