Tissue Layers

Diploblast
2 tissue layers
Usually radial symmetry
Tripoblast
3 tissue layers
Bilateral symmetry

Cnidarians

Polyp
Sesile
Medusa
Motile
Are Diploblastic
Ectoderm
Nerve nets
Epidermal cells contract for movement.
Endoderm
Gastrovascular cavity
Not a 'complete' gut.