Practice question

Despite colonial modular construction ectoprocts possess organization as true eucoelomates with compartmentalized coelomic cavities lining gut and body wall derived from mesoderm bordered by ciliated peritoneal mesothelium containing coelomocytes. Coelomic fluid functions as hydrostatic skeleton, pressure generated by contraction of parietal muscles protrudes lophophore for feeding, accommodates retractor bundles pulling polypide inside zooecium. Each autozooid possesses separate coelomic compartment though reduced due to small size. Presence aligns ectoprocts with phoronids and brachiopods as coelomate lophophorates distinguishing them from acoelomate platyhelminths or pseudocoelomate nematodes correcting former interpretation as acoelomate or diploblastic organisms historically misclassified in textbooks.