Sponges of the family Cladorhizidae have given up filter feeding: the canal system, the flagellated choanocytes and the osculum are reduced or absent. In their place the body surface is armed with microscopic hook-shaped spicules, and small swimming crustaceans that brush against a branch are held mechanically, without stinging cells or adhesive. Chondrocladia is the family's exception, keeping a rudimentary water canal system and choanocyte chambers, but these inflate its terminal spheres rather than gather food.
Digestion follows slowly. Cells migrate over the captured prey, enclosing it in a membrane, and break it down externally before absorbing the products. The harp form itself is a surface-area solution: parallel vanes, each with dozens of upright branches, present a wide interception screen to the slow current near the seafloor.
This is a genuine reversal of a defining trait, evolved in deep water where suspended food particles are scarce and small swimming prey is relatively more available. The details remain thin, since the group is known from a small number of specimens and video observations, and prey capture has rarely been watched directly in the wild.