How many body parts does a starfish have?

Starfish have an endoskeleton comprised of many little bones.

Since the term starfish encompasses a whole host of different creatures with different numbers of arms, I presume the answer isn't well defined. All the skeletons I've seen have a huge number of intricate bones, but I haven't seen that many.

Term bones doesn't 'easily' apply to the phylum echinodermata. What solid spines and plates they have are part of their skin, and what gives their bodies their rigidity is a 'water vascular system' or a Hydro-skeleton' or a 'pneumatic skeleton', which depends on water pressure to make it function.