Luzon Island, Philippines
The white projections from the arm stalks in this closeup view are called pinnules. This crinoid has its arms retracted. Though many may feed during daylight hours, crinoids normally are nocturnal, and commonly keep the arms in a retracted position during the day. The tiny cilia lining the pinnules are also retracted and not visible in this photo.
Jeffrey N. Jeffords (photographer; copyright holder; identification)
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