1. Class – Calcarea (Calcispongiae)
• The skeleton is of spiculues made up of CaCO3.
• Examples – Leucosolenia, Syncon, Grantia, Leucilla etc.
2. Class – Hexactinillida (Hyalospongiae)
• The skeleton is of spicules made up of silica.
• Examples – Hyalomena, Euplectella, Pheronema etc.
3. Class Demospongiae
• The skeleton is of sponging fibres.
• Examples – Euspongia, Spongilla, Chalina, Cliona Spheceospongia etc.