The oral siphon is surrounded by a ring of branched tentacles, the function of which is to prevent large particles being drawn into the pharynx with the water current.

Sand grains and shell fragments adhere to its tunic, completely covering the surface apart from a small area in the immediate vicinity of the siphons.

[1][5] Molgula oculata is a suspension feeder, filtering planktonic particles and bacteria from the water which is pumped continually through its body.

In the laboratory, the two have been hybridised and it was found that the larval offspring of the occulta x oculata hybrid possessed a half length tail and an otolith.

The researchers hypothesized that both species were descended from a common ancestral line but that at some stage, M. occulta had lost part of its genome.