Blumenbach, 1798
Solitary zooids
Test cylindrical, thickened ventrally around the nucleus, with two long posterior projections (Thalia cicar, Thalia democratica, Thalia longicauda, Thalia orientalis). Oral opening terminal, atrial opening postero-dorsal. Intermediate muscle prominent and interrupted dorsally. Five body muscles, MI to MIV, continuous dorsally and ventrally, MV interrupted ventrally. Nucleus compact, stolon coiled around it.
Aggregate zooids
Body oval, rounded or pointed posteriorly (Thalia democratica 2, Thalia longicauda 1, Thalia orientalis 1). Five body muscles fused dorsally into two groups: MI to MIII and MIV to MV; all the muscles interrupted ventrally. Nucleus compact. Testis arranged in 4 lobes. Ovary and embryo near MV.
Seven recognized species, 4 of which have been recorded from the South Atlantic Ocean. Usually the solitary zooids of these species can be recognized readily, whereas aggregate zooids of Thalia democratica, Thalia cicar, and Thalia orientalis cannot be separated clearly on the basis of their morphological characters.
Thalia cicar Van Soest, 1973
Thalia democratica (Forskål, 1775)
Thalia longicauda (Quoy and Gaimard, 1824)
Thalia orientalis Tokioka, 1937