| Crinoid, Cladida, Echinoderm, Monobathrida, Articulata|Camerata (Crinoidea) Wikipedia
The Camerata or camerate crinoids are an extinct subclass of Paleozoic stalked crinoids. They originated in the Middle Ordovician and became extinct in the end-Permian mass extinction, and reached their maximum diversity during the Mississippian.
Anatomically, they are distinguished by: fused junctions between the plates of the cup
brachial plates incorporated into the cup
tegmen forming a rigid roof over the mouth
no less than ten and sometimes a very large number of free arms, often pinnulate