Compare the structural features of coelenterates and flatworms. List the signs indicating a higher organization of worms

Compare the structural features of coelenterates and flatworms. List the signs indicating a higher organization of worms in comparison with coelenterates.

Distinctive features of coelenterates.
The symmetry of the body is radial;
Two germ layers – ectoderm and endoderm;
The body has a two-layer wall;
The presence of a gastric cavity;
Diffuse nervous system.

Special features of flatworms:
The symmetry of the body is bilateral;
3 germ layers – ectoderm, endoderm, mesoderm;
The presence of a skin-muscle bag;
Hermaphrodite type, the presence of organs that provide the possibility of internal fertilization;
The respiratory and circulatory system is absent.