It was interesting to see this small California berthella (Berthella californica) moving along a rock wall. Although this animal does look like a nudibranch, it has a very thin white internal shell. There are also wide lateral tissue extensions that spread beyond the foot, and this upper layer is covered with white spots. The rhinophores look different in that they are rolled into tubular projections. Also, a single gill is located on the right side of the body between the foot and the lateral extensions. The California berthella can grow to 2 inches (5 cm) long, with a range that includes Siberia, the Galapagos Islands, as well as southern Alaska to northern Mexico.