Hemichordata is a phylum under Non-chordates. It was initially considered as chordates but later on was included as a part of Non-chordates. These organisms show presence of a hollow outgrowth which was considered to be notochord but it was seen that its origin is from buccal cavity and thus it was named as stomochord (stoma is mouth). Balanoglossus and Sacoglossus belong to this phylum.