Order 1. Myxospongia.—G elatinous ; no skeleton : Hdlisarca. 
Order % Fibrospongia.—W ith fibrous skeleton • \ 11 y * Svona ^ a ‘ 
' ( siliceous: Jzuptectella. 
Order 3. Caloispongia.—S keleton calcareous, not fibrous: Sycon. 
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