The jellyfish which you have been studying is the large, sexual, freeliving, pelagic, motile medusoid generation . From it develops the asexual, sessile, benthic, inconspicuous polypoid generation . Aurelia is gonochoristic. Spermatozoa are released from the gonads into the gastric pouches and then out the mouth into the sea. They enter the mouth of a female and make their way to the gonad where they fertilize the eggs.
Cleavage begins in the gastric pouches.
Embryos are released from the mouth and brooded on the oral arms. A hollow, ciliated blastula develops and invaginates to become a gastrula. The gastrula, also known as the planula larva, is capable of independent existence and is released from the mother into the plankton. The planula locates an appropriate hard substratum, attaches, and grows into a polyp. The planula is an ovoid gastrula with a blastopore at one end and a long narrow blastocoel in the interior.