(i) Coelomate: There are two germinal layers in coelomates, viz. ectoderm, mesoderm and endoderm. The mesoderm lines the body cavity ad thus body cavity  is
present.
(ii) Acoelomate: There are two germinal layers in acoelomates, viz. ectoderm and endoderm. Body cavity is not present in coelomate.
(iii) Pseudocoelomate: There are three germinal layers in pseudocoelomate, viz. ectoderm, mesoderm and endoderm. But mesoderm is present as scattered
pouches and hence true coelom is absent.