Yes, a protostome is, and so is a deuterostome. Neither are diploblastic. This is mainly because of the developement of the coelem or body cavity. Just remember, both protosome and deuterostome require a three germ layer (that is a triploblastic cell) - ALWAYS
no they are neither deuterostome nor prostome because they dont have an alimentary canal. so how can they be any of them? deuterostome are those in which anus forms first then mouth whereas sponges dont have any organ as they are loose aggregate of cells and digestion is intracellular.
Deuterostome coelomates are divided into 2 groups : the epithelioneurians and the epineurians/chordates , Epithelioneurians (whose nervous system is a network of nerve fibers related with the epithelium) have a rudimentary cephalization
Protostomes. Development begins with spiral, determinate cleavage. Coelom formation then begins in the gastrula stage, the coelom forming from splits in the mesoderm. The mouth then develops from the first opening, the blastopore, and the anus develops secondarily.