Chitons have a dorsal shell which is composed of eight separate shell plates or valves. These plates overlap somewhat at the front and back edges, and yet the plates articulate well with one another. Because of this, although the plates provide good protection for impacts from above, they nonetheless permit the chiton to flex upward when needed for locomotion over uneven surfaces, and also the animal can slowly curl up into a ball when it is dislodged from the underlying surface. The shell plates are surrounded by a structure known as a girdle.
Here is the shell of one we saw back on September 22, 2010:
|According to Wikipedia, chitons have "a dorsal shell|
which is composed of eight separate shell plates or valves."
Below is the live one seen yesterday, on March 22, 2011:
|See it's foot? Wikipedia says, "A chiton creeps|
along slowly on a muscular foot. They have considerable
power of adhesion and can cling to rocks very powerfully,
like a limpet."