Boltenia ovifera is a species of ascidian tunicate in the family Pyuridae. It is found in the Arctic to the South of Cape Cod. Boltenia ovifera has an average lifespan of 3 years and it can house small invertebrate creatures like the red king crab. They group in long stalks around 20–30 centimetres (7.9–11.8 in), they are found in the ocean on a substrata around 10–300 metres (33–984 ft). Under a microscope it was observed that they have spines on their external surface. Inside the tunic, no real organized cellular system was observed. It was also noted that they have a single layer heart, where each cell had a single microfibril.