ClipArt ETC
Diagrams of the body layers and cavities in A, coelenterates; B, flatworms; C, annelids; D, vertebrates. Labels: G, gastric cavity; g, cavity of the gonad; a, primary body cavity (blastocoele) filled with branched cells (mesenchyme); c, secondary body cavity (coelom); d, dorsal mesentery; m, mesenchyme filling space of original primary body cavity; n, nerve tube.

Body Layers and Cavities

Diagrams of the body layers and cavities in A, coelenterates; B, flatworms; C, annelids; D, vertebrates.…