The viscera extend only around halfway down the abdomen, so the posterior part of the tapered body is empty and is where the eggs of this hermaphrodite organism develop. The large wing-like parapodia project well beyond the sides of the body. Other remnants of the foot are represented by three lobes situated centrally behind the head, two lateral and a median one. There are no gills, unlike the related Pneumodermopsis spp.
In fresh specimens the body is transparent, while the organs in the anterior body are coloured red/orange, especially the buccal cones and round the mouth. The posterior tip of the body is also coloured. Clione often occurs with the thecosome Limacina retroversa, on which it feeds (Figure 24B). This association develops from an early age, as after the veliger looses its shell, it starts feeding on Limacina veligers. Size: 2-15 mm in the south, up to 45 mm in the Arctic.