I was intrigued with your posts of jellyfish being microscopic , so I called the crazy horse lady and she sent me this link ,told me to figure it out and call her back with my answer. Only thing I can get from this article is the family tree chart and nematodes being a part of the ancient jellyfish family??? I will need to research that though so I can give her an educated guess. Another thought is jellyfish molt in different stages like nematodes , and maybe jellyfish have a larvae stage . It must have been a good question because she provided me a link.