I am looking for an embryological perspective on the following question.
I know about coelom derivation, but I want to know how haemocoel is derived and how it is fundamentally different from coelom.
True coelom is formed by the cavity formed in mesoderm. It is lined by mesothelium on both sides, whereas on the other side pseudo coelom is cavity which is lined by endothelium and mesothelium. However, the formation of haemocoel is not clear to me.
I have looked for in many books, but I have not been able to find an embryological perspective and what happens to coelom in which haemocoel is present.