Solitary zooids: up to 12 mm long, excluding posterior projections (Thalia democratica, Thalia democratica 1). Test smooth, atrial palps simple and straight, lateral and mid-ventral projections small; all test projections echinate. MI to MIII and MIV to MV contiguous or fused dorsally over a short distance. Number of muscular fibers, including the intermediate muscle: 37-86.
Aggregate zooids: nucleus bearing a posterior projection (Thalia democratica 2). Number of muscular fibers (MI-MV): 15-17, usually 16.