Fertilisation is internal. Egg cleavage is total, equal, and typically radial. The larvae undergo a planktotrophic development during 2-3 weeks and settle after about 20 days. They occur at depths ranging from the intertidal zone to about 400 m depth, but mainly between 0 to 70 m. The life span is thought to be about one year.
Phoronids are suspension-feeders.
They orient their lophophores into the prevailing water current. Direct uptake of amino-acids through the epidermis displays seasonal variations. Emig C. C., 1976. Emig C. C., 1979. British and other Phoronids.