They are characterized by their aboral face formed by plates shaped like crescents, sometimes giving a "knitted" appearance to the skin.

[2] The abyssal species can be bigger, like those of the genus Anseropoda, which can exceed 45 cm in diameter.

For that reason, some species of the genera Meridiastra and Aquilonastra can sometimes appear spontaneously in aquariums, where they can proliferate from just one larva imported inadvertently.

Some species can brood their young (which thus do not pass through a planctonic larval stage), such as Asterina pancerii.

However, some species like Stegnaster inflatus takes advantage of their webbed shape to form a "trap" by heightening on the tip of their arms, and suddenly falling on a prey which would have believed to find shelter there.