Jenis Crinoid Feather Stars

Physical Traits
Living Crinoid
• They are attached suspension-feeding echinoderms with a cuplike body
supported upward by a stalk or claws (cirri).
• They have a mouth on the top surface facing up surrounded by usually 5
featherlike feeding arms.
• All echinoderms have pentameral symmetry (organization in patterns of 5) and
crinoids can have as few as 5 arms, but usually have arms in multiples of 5.
• They have a u-shaped gut and their anus is located next to the mouth. They also
have sticky mucus covered tube-like feet.
• Most of their body consists of an endoskeleton composed of many calcareous
(composed of calcium carbonate) pieces embedded in their skin called plates or
ossicles.
• The crinoid is encased in the aboral cup, which is typically composed of 2-3
circles of plates.
• Five radial plates (the uppermost circlet of aboral cup plates) are aligned with the
radial water vascular canals and give rise to five arms on the oral side of the
body.