Breimer (1978) suggested that for crotalocrinitid feeding the arms could create ciliary feeding
currents through this shield.
Evolution of ciliary feeding
in the Prosobranchia, with an account of feeding in Capulus ungaricus.
In an apparently similar kind of ciliary feeding by sessile animals (sabellid and serpulid annelids, entroprocts), the opposed bands are composed of cilia of equal length (Henderson and Strathmann, 2000; Riisgard et al., 2000).
If a ciliary feeding mechanism of veligers is direct interception, what allows the cilia to adhere to particles and not lose them to tangential drag forces as they are swept toward the food groove?
assisted by suction from the muscular oral hood of phoronid larvae.
Although high-speed recordings are lacking for ciliary feeding by larvae of other echinoderm classes and of hemichordates, the morphology of ciliary bands and the particle paths near feeding and non-feeding larvae suggest that these larvae also capture particles by an induced local reversal of beat (Strathmann, 1971; Strathmann and Bonar, 1976; Hart, 1991, 1996b; Hart et al., 1994).
Ciliary feeding of tornaria larvae of Ptychodera flava (Hemichordata: Enteropneusta).
The combination of two ciliary feeding
mechanisms in individual larvae suggests hypotheses for evolutionary transitions among the feeding larvae of annelids.
The hood lift supplements a ciliary feeding
mechanism but has not replaced it.