Sunday, January 28, 2007
Ah, came across
THIS webpage while surfing aimlessly between periods of study.
"All crinoids are passive suspension feeders. They produce no feeding/respiratory current but, rather, rely on extrinsic, ambient water movement. In extant crinoids, the food-gathering apparatus functions as follows: each featherlike arm that radiates from the central body bears an open ambulacral groove bordered by triads of fingerlike podia, or tube feet, which are terminal extensions of the water vascular system. The longest tube foot in each triad, 0.43-0.85 mm in length, is held out at a right angle and flicks passing food particles into the groove. After a food particle is captured by a crinoid, the shortest tube foot wraps it in mucous secretions; ciliary tracts on the groove floor then transport it toward the mouth. In living crinoids, food particle size ranges from about 50 to 400 µm. Diets include a variety of protists (e.g., diatoms and other unicellular algae, foraminiferans, actinopods), invertebrate larvae, small crustaceans, and detrital particles."
OK, so the flicking thing I caught on video is the feeding mechanism! And they do have tube feet. The oyster eggs have the right particle size for them, so hopefully it'll do well. The crinoid lost a couple of feathers while at the coral wholesaler's, but they're actually growing back - a good sign of growth.
Wenky
1:13 PM
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