from the embryos

Becuase I want my creatures to be more plausible, I have decided to reaserch on the stages in which babies are born. Then, I will create the creatures from their embryonic stage and morph them into their grown up stage.
Here is a representation of vertebrate embryology drawn by a well known evolutionary biologists, Ernst Haeckel. Although there has been some questions about the authenticity of these drawings, I think I will focus more on the visuality and less of the sciences.