Triploblastic means having three germ layers: ectoderm, mesoderm, and endoderm. This is seen for the first time in the phylum Platyhelminthes. These are flatworms that exhibit bilateral symmetry. These do not show any body cavity hence are acoelomates. Example: Tapeworms, liver flukes etc. These reproduce by asexual and sexual manner. Thus only this phylum is triploblastic but are acoelomates.