Chitons are ubiquitous on the beach. We believe the one pictured below is a woody chiton, or Mopalia lignosa. (It may also be a mossy chiton, visit this site if you care about the differences between the two.) Species in the genus Mopalia differ from other chitons in that they eat both animal and vegetable material and are covered in bristly hairs. But even though the woody chiton is capable of eating meat, it still feeds primarily on sea lettuce. Like other chitons, its body is protected by eight overlapping calcareous shell plates, which look like a knight's armor, and give chitons their colloquial nickname "coat of mail shells." For the record: we've never heard anyone call a chiton a coat of mail shell. woody chiton from the top: 
from the bottom:
and underwater (courtesy of Ed Bierman on Flickr):
[…] of meat eaters, and they make for good viewing but bad algae control. So decided to introduce a chiton into the mix. The problem is that it takes animals a while to acclimate to the warmer temperatures […]