Crinoidea
Class Crinoidea are the feather stars and sea lilies. Sea lilies are restricted to the deep water and are permanently attached to the sea floor. Feather stars perch and crawl on the sea floor both in the shallows and in deep water. They are also capable of swimming.
The body plan of a crinoid can be viewed as an upside-down brittle star with the ambulacral grooves and mouth pointed upward. The mouth and larger organs are restricted to a small cup-shaped body from which the arms branch out. Some crinoids have 5 arms but most have many more than that (up to 200!) The arms have small side branches as well where the tube feet secrete mucus which aids in catching food particles. Food makes its way into the mouth via ciliated ambulacral grooves. The feather stars tilt their bodies so that the extended arms orient toward currents for better suspension feeding.
The body plan of a crinoid can be viewed as an upside-down brittle star with the ambulacral grooves and mouth pointed upward. The mouth and larger organs are restricted to a small cup-shaped body from which the arms branch out. Some crinoids have 5 arms but most have many more than that (up to 200!) The arms have small side branches as well where the tube feet secrete mucus which aids in catching food particles. Food makes its way into the mouth via ciliated ambulacral grooves. The feather stars tilt their bodies so that the extended arms orient toward currents for better suspension feeding.