An order of exclusively deep-sea asteroids (sea stars or starfish) possessing an unusual body form adapted for suspension feeding. These adaptations in the Brisingida (also called brisingids or brisingidans) include having 6–20 elongate arms (there are no known 5-rayed brisingids), a small inflexible disk with a large mouth, and long needlelike spines that project off the arms in distinct series. Brisingids practice suspension feeding, which is a way of obtaining food that involves water current filtration through the arms as they are upheld in the water (similar to what is seen in Fig. 1). Observations from submersibles have shown living brisingids with their arms extended into the water current with their disk and mouth tube-foot grooves facing downward, but open to the surrounding water. It is not uncommon to observe large aggregations of brisingids in settings, such as cliffs and rock formations, where water current is optimal for feeding.  See also: Asteroidea; Echinodermata