strongylocentrotus

Chitons & Urchin by marlin harms
Via Flickr:
Another one from the archives. Chitons: left–Tonicella lineata, Lined Chiton or Tonicella lokii, Loki’s Chiton; right–Mopalia lignosa, Wood Chiton or Woody Chiton. Urchin: Strongylocentrotus sp. The chitons were probably near 2" (5cm) long. Montana de Oro State Park, San Luis Obispo Co., CA