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• Crinoid stems in limestone matrix •
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Most crinoids had a foot-like bottom section called a holdfast or root that it used to anchor itself to the sea floor. Above this foot-like section was the stem that supports the animals crown of arms that waved with the ocean movement. At the center of this crown of arms is the calyx, which contains the vital organs of the animal. The calyx is small when compared to the total mass of the crinoid, most of which is devoted to food collection. The mouth and anus are located on the upper surface of the body, and are connected by a simple gut. The arms at the crown are composed of an articulated series of ossicles that are used in suspension feeding and respiration. The gonads are also located in the arms; fertilisation takes place in open sea water during mass spawning.
While most crinoids were stalked animals, rising from the sea floor with their stems, there are a number of species that are "free floating" crinoids, not being anchored to the sea floor. Scientist believe that during the long span of time that crinoids have existed, that there have been over 600 species.
| Price: $80.00 (24 Pc.) |
| BTF-124 Crinoid stems in limestone matrix (Tennessee) |
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