The flatworms are acoelomate triploblasts i.e., they lack a body cavity and have three embryonic tissue layers: endoderm, mesoderm, and ectoderm. |
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The body plans that are generally recognized are acoelomate, pseudocoelomate, and coelomate. |
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These basal triploblasts were assumed to be acoelomate worms represented by todays platyhelminths, with no segments and coelom and bearing a blind gut. |
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