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Crinoid Sea Floor Replica measures 12×7 inches. Crinoid sea floor replica is museum quality, polyurethane resin replica made in the USA.
They are marine animals that make up the class Crinoidea, one of the classes of the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers.
Those crinoids which, in their adult form, are attached to the sea bottom by a stalk are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, being members of the largest crinoid order, Comatulida.
Adult crinoids are characterised by having the mouth located on the upper surface. This is surrounded by feeding arms, and is linked to a U-shaped gut, with the anus being located on the oral disc near the mouth.
Although the basic echinoderm pattern of five fold symmetry can be recognized, in most crinoids the five arms are subdivided into ten or more. These have feathery pinnules and are spread wide to gather plank tonic particles from the water.
At some stage in their life, most crinoids have a stem used to attach themselves to the substrate, but many live attached only as juveniles and become free swimming as adults.
There are only about 600 living species of crinoid, but the class was much more abundant and diverse in the past. Some thick limestone beds dating to the mid to late Paleozoic era are almost entirely made up of dis-articulated crinoid fragments.
The crinoids were almost wiped out by the extinction event at the end of the Palaeozoic era. Four whole classes became extinct, and the few that survived became the only living class, the Articulata.
The stalked members of the class sufered from heavy predation in the Mesozoic. Now all the remaining sea lilies are in deep water, where the competition is less fierce. The feather stars have been much more successful.
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|Dimensions||12 × 7 in|