Water flows through the osculum in and out of the central cavity, called the spongocoel.  
Members of this phylum possess gelatinous mesohyl regions through which food-collecting amoebocytes travel.  Most are hermaphrodites, lack nerves and muscles, and were not regarded as animals until the eighteenth century.  Water flows through the osculum in and out of the central cavity, called the spongocoel.  FTP, identify this invertebrate phylum which includes the sponges.
Members of this phylum possess gelatinous mesohyl regions through which food-collecting amoebocytes travel.  
Porifera  (prompt on early "sponges")