What are the two main morphological patterns of cnidarians? Concerning locomotion how do these forms differentiate from each other?

Morphologically, cnidarians categorize as polyps or medusae. Polyps are cylindrical and medusae are circular convex, such as an umbrella. Both shapes have tentacles.

In general polyps are sessile but some species, as hydra, can move by alternating contact points on the performing somersaults and substrate. Medusae can move expelling water jets by contraction of the body.

Some cnidarians alternate polypoid and medusoid produces in their life cycle.

Image Diversity: polyps medusae