n. Phylum Chordata, Subphylum Urochordata. A group of boneless chordates whose members begin life as tailed larva and often settle to a sedentary existence devoted to filtering seawater for a living.

Marine chordate animals with a thick covering layer, including sea squirts; of the Subphylum Urochordata

An invertebrate animal of the subphylum Urochordata.

Small, primitive chordate animals that live attached to rocks or to the seafloor. Many species of tunicate live in the intertidal zone, and some, like the predatory tunicate, live in the deep sea. Some tunicates are called "sea squirts" because they squirt water when disturbed.

Urochordata (sometimes known as tunicata and commonly called urochordates, tunicates, sea squirts or cunji) is the subphylum of saclike filter feeders with incurrent and excurrent siphons. There are also a few exceptions to this plan, like the predatory Megalodicopia hians, looking something like a cross between a jellyfish and a Venus Flytrap. They are members of the phylum Chordata, which also includes lancelets, hagfish and all vertebrates including humans.