Deposit feeding in Abra tenuis is described in terms of the size of particles utilized.
Material is collected by the inhalant siphon performing a circular motion sucking in sediment from beneath and on the surface.
The size distribution of silica admitted into the mantle cavity is described and shown to be controlled by physical parameters. The density of a particle does not affect its uptake by the inhalant siphon. The size distribution of the sediment affects the size distribution of particles admitted to the mantle cavity.
No selection of material for ingestion in terms of size occurs after it has been taken into the mantle cavity. Thus the range of material ingested is ultimately controlled by a physical parameter, the inhalant opening.