Solitary zooids: up to 140 mm long (Pegea socia). Yellow reticulate pigmentation in broad band along each side of body. Nucleus reddish brown. Test thicker than in Pegea confoederata. MI to MII fused across the mid-dorsal line for about 0.25 of their length; MIII to MIV contiguous but not fused. Mean number of muscular fibers: MI: 41; MII: 35; MIII: 24; MIV: 21. Mature stolon describing two complete turns around the gut.
Aggregate zooids: up to 120 mm long (Pegea socia 1). Body uniformly covered with finely reticulate golden pigmentation, nucleus orange. MI to MII and MIII to MIV barely contiguous dorsally, MIV extending further laterally than other muscles. Mean number of muscular fibers: 30 in each muscle.