Why are the cnidarian animals known as bilayered animals?

Why are the cnidarian animals known as bilayered animals?

The embryos of the animals in which there are only layers - ectoderm and endoderm are called bi-layered animals. In between these two layers, there is an acellular jelly-like structure called mesoglea. All the animals of the Cnidaria phylum are bi-layered. For this reason, the cnidarian animals are known as bi-layered animals.