How would you differentiate between Protostomia and Deuterostomia ?

Explanation

Large number of animals have tube-within-tube body plan. This planis of two types `:` protostomous and deuterostomous.
In protostomous plan, mouth is derived from the blastopore of the embryo and the anus is formed at the opposite end. This plan is found in most nonchrodates ( flatworms, roundworms, annelids,molluscs and arthropods) . These animals form the group termed Protostomia.
In deuterostomous plan, anus develops from the blastopore and the mouth arises at the opposite end. This plan is seen in the echinoderms, hemichordates and chordates. These animals constitute the group deuterostomia.