Solitary zooids: up to 35 mm long (Ihlea magalhanica, Ihlea magalhanica 1). Body muscles usually arranged as in Ihlea racovitzai but without the ventral spur of MI. Also, both branches of MVII remain fused dorsally over a wide area, whereas MIV and MV are separated ventrally. Number of muscular fibers of MII: 77-148. Stolon exiting ventrally, immediately ahead of the nucleus.
Aggregate zooids: up to 15 mm long (Ihlea magalhanica 2, Ihlea magalhanica 3). Body muscles arranged as in Ihlea racovitzai. Number of muscular fibers of MII: 25-40. Two embryos behind MIV. Up to 12 oocytes in young zooids (Daponte and Esnal, 1994).