Sea Pens
Ptilosarcus gurneyi

f16 @ 1/60s, Kodachrome 64 slide film, ASA 64, Nikonos II w 15mm, Oceanic flash


"Sea Pens," Wikipedia, the free encyclopedia. Sea pens are sometimes brightly coloured; the orange sea pen (Ptilosarcus gurneyi) is a notable example.As octocorals, sea pens are colonial animals with multiple polyps (which look somewhat like miniature sea anemones), each with eight tentacles. Unlike other octocorals, however, a sea pen's polyps are specialized to specific functions: a single polyp develops into a rigid, erect stalk (the rachis) and loses its tentacles, forming a bulbous "root" or peduncle at its base. The other polyps branch out from this central stalk, forming water intake structures (siphonozooids), feeding structures (autozooids) with nematocysts, and reproductive structures. The entire colony is fortified by calcium carbonate in the form of spicules and a central axial rod.
Edmonds, Washington
 
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