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316 American Seashells
lated with browns and yellows. Strap-like, brown hairs not numerous. Interior
of valves greenish white to white. Moderately common.
Mopalia hindsi Reeve Hinds' Mopalia
Alaska to the Gulf of California.
2 to 3 inches in length, oblong, flattened and resembhng M. ciliata
Sowerby, but generally smoother. Girdle brown, rather thin and fairly
wide, and almost naked except for a few short hairs. Interior of valves
white with short crimson rays under the beaks. Moderately common.
Genus Placiphorella Dall 1878
Placiphorella velata Pilsbry Veiled Pacific Chiton
Monterey, California, to Lower California.
Figure 66a
1 to 2 inches in length, readily recognized by its flat, oval shape and
wide girdle which is very broad in front. There are a few hairs on the
girdle which, if viewed under a lens, will be seen to be covered by a coat
of diamond-shaped scales. Girdle reddish yellow. Valves colored a dull
olivaceous brown with streaks of buff, blue, pink or chestnut. Interior
of valves white with a slight bluish tint. Posterior valve with i to 2 slits
and with very large sutural plates. Fairly common intertidally.
Genus Katharina Gray 1847
Katharina tunicata Wood Black Katy Chiton
Aleutian Islands to southern California.
Figure 66b
2 to 3 inches in length, oblong and elevated. Characterized by its shiny,
naked, black girdle which covers % of each gray valve. Valves usually
eroded. Anterior valve densely punctate. Interior of valves white. Foot
salmon to reddish. Very common between tides, especially in the north.
Genus Syimnetrogephyriis Middendorff 1847
(Amicula Gray 1847, not 1842)
Symmetrogephyrus vestitus Broderip and Sowerby Concealed Arctic Chiton
Figure 66c
Arctic Seas to Massachusetts Bay. Arctic Seas to the Aleutian Islands.
I to 2 inches in length, oval, rather elevated. Valves covered with a
thin, smooth, brown girdle except for a small, heart-shaped exposure at the