Ascidiacea

Japanese: Ascidiacea

…a class of protochordata. All of them live in the sea and include four orders: Appendicularia, Thaliacea, Pyrosomata, and Ascidiacea. When young, urochordates are tadpole-shaped and have a notochord in their tails, but when they metamorphose and begin to live epiphytically, the notochord and the muscles of the tail are absorbed into the head and are no longer visible.

From [Hoya (sea scaly)]

…A general term for protochordata belonging to the Ascidiacea order of the class Urochordate. All of them live in the sea and attach to various objects such as reefs, the surfaces of shells, the bottoms of ships, and various underwater equipment.

*Some of the terminology that mentions "Ascidiacea" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…原索動物門の1綱。すべて海産で，尾虫目Appendicularia，サルパ目Thaliacea，火体目Pyrosomata，ホヤ目Ascidiaceaの4目を含む。尾索類の幼時は，オタマジャクシ形をしていて，尾の部分に脊索が見られるが，変態して着生生活にはいると，脊索と尾の筋肉がいっしょに頭の部分に吸収されてまったく見られなくなる。…