Mouth on ventral side of the collar. Tentacles on the head like a lophophore. Many pairs of gonads in the trunk coelom.
Eggs cleave radially.
B Taxonomy of the Phylum. Proboscis cilia collect food. Saccoglossus, Spengella, Balanoglossus. Rhabdopleura, Cephalodiscus, Atubaria. Assumed to be the larval stage of an unknown hemichordate.