What is true coelom?
The body of some animals is made up of three layers of cells, the outer ectoderm, the middle mesoderm and the inner endoderm. The body cavity or the coelom is the space enclosed by the mesoderm where the internal organs are suspended. Some animals do not have a true coelom but the mesoderm is present in scattered pouches. Such animals are said to be pseudocoelomic. For example Phylum Nematoda. The animals that have a true body cavity are known as coelomic or eucoelomic. For example, phylum Annelida.