This colonial ascidian is usually found as a densely-packed and often elongated colony, growing on a tube of basal test. There is some variation in colony shape, as well as colouration, which can be an opaque white, whitish-blue, or clear and transparent. The opaque colonies are unique in the waters of southern Australia, but the transparent colonies can be hard to distinguish from the more common Clavelina moluccensis. Notwithstanding the differences in colony shape, transparent C. cylindrica colonies can be further distinguished by the single blue pigment spot between the zooid siphons, as opposed to the row of three that are present in c. moluccensis. Note that the opaque colonies rarely have any visible pigment spots.
