Oikopleura (Vexillaria) vanhoeffeni is a rather large appendicularian species. The trunk is compact. The left lobe of the stomach is round. Ovary and testes together forming a round structure behind the stomach and oesophagus. The endostyle is long and narrow, at each side accompagnied by an ovoid buccal gland.
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 are numerous small glands.