Pelagic tunicates in the China Seas Author Franco, P. Author Dahms, H. - U. Author Lo, W. - T. Author Hwang, J. - S. text Journal of Natural History 2017 2017-03-27 51 15 - 16 917 936 http://dx.doi.org/10.1080/00222933.2017.1293180 journal article 10.1080/00222933.2017.1293180 1464-5262 5180954 Oikopleura ( Vexillaria ) rufescens Morphology A large appendicularian species. The trunk is compact with a length of 2–7 mm and the tail is long with a strong chord and medium-sized muscular bands. At the right side of the proximal third part of the tail, there are small sub-chordal glands. The endostyle is long and narrow, and at each of its sides it is accompanied by an ovoid buccal gland. The left lobe of the stomach is round. A lower lip is present in juveniles; adults possess a membraneous lip. The ovary and testes are together forming a round structure behind the stomach and oesophagus ( Marine Species Identification Portal 2017 ). Biogeography Typical cold-water appendicularian species from the Arctic , the northern North Atlantic and northern North Pacific Oceans (being most abundant north of 60°N ) (WoRMS Editorial Board 2017 ) .