Small orange dirty pink urn shaped lobes (2-3 cm long, 1-2 cm in diameter), attached by a common basal mass and form large colonies (5-15 cm in diameter).
Zooids (2-3mm long) arranged in systems, short branchial opening long atrial siphon.
Branchial aperture open on the outside of the urn shaped lobes, atrial opening on the inner surface into a large common cloacal cavity.
Colony fleshy with inner test translucent, spicules star-shaped with sharp points.
Branchial sac with 4 rows of 14-20 stigmata, no retractor muscle.
Gonads over the posterior end of gut loop, ova next to single testes follicles with sperm duct in 9-11 coils over it.
Monniot, C.; Monniot, F.; Griffiths, C. and Schleyer, M. 2001 Ascidians of South Africa.108:1-141
Shenkar, N.; Gittenberger, A.; Ruis, M.; Rocha, R. M.; Swalla, B.; et al. 2017 Ascidiacea World Database. Atriolum marinense Kott, 2001. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=250052 on 2019-03-12