Question

Why platyhelminthes and nematodes have pseudocolem

Answer 1

Nematodes and platyhelminthes do not have completely developed mesodermal lining cavities called coelom. They have cavities that are not formed completely by mesoderm. They have a body cavity but it is not lined with mesodermal cells. It exists between the mesoderm and the endoderm that makes up the walls of the gut.Thus they are not true coelom and are known as pseudocoelom.