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PORIFERA 



PORIFERA. 



1. Leucosolenia. Simple calcareous sponge (Ascon type). Osculum. The surface is rough with 

 projecting calcareous spicules. 



2. Grantia. Calcareous sponge (Sycon type) : colonial form. Narrow elongated oscula. 



3. Transverse section through Leucosolenia. Gastral cavity with collar-cells ; radial canals ; 

 mesoglcea with ova ; spicules. Draw outline from low power, fill in details from high power of 

 decalcified specimen. 



