Tunicate

Tunicates, also known as urochordates, are members of the subphylum Tunicata or Urochordata, a group of underwater saclike filter feeders with incurrent and excurrent siphons that is classified within the phylum Chordata. While most tunicates live on the ocean floor, others – such as salps, doliolids and pyrosomes – live above in the pelagic zone as adults. They were historically known as Ascadia, and are now commonly known as sea squirts and sea pork.