Are sea stars coelomates

Think of it this way. In sea star development, the last stage is the late gastrula, as development continues, two pouches (the coelomis sacs) form by outpocketing from the endoderm surrounding the gut. These pouches become part of the coelom (body cavity), and the walls of the lateral pouches become the third germ layer, the mesoderm.

I got this information from my college lab manual, Inquiry Into Life, Thirteenth Edition