• Marine, free – swimming pelagic thaliacean.

• Life cycle exhibits alternation of generations.

• Sexual phase called Solitaria phase and asexual phase called gregaria phase.

• Atrial and branchial apertures are at the opposite ends.

• Branchial cavity opens to atrium by a pair of large gill slits.

• It is a protogynous hermaphrodite.

• Solitaria phase is represented by Oozoid and gregaria phase by Gonozooid.

• Direct development.