Strobilation

The moon jellyfish (Aurelia aurita) reproduces both sexually, and asexually  in a process indicated as strobilation. This process occurs during the colonial polyp stage and produces either polyps or juvenile medusae called ephyra. Strobilation tend to occur at specific periods, typically early spring.

Aurelia aurita - Strobilation. Diluted Indian ink,  2012 (30 x 20 cm) 

The reproduced drawing has no claim to scientific accuracy, but it  draws attention to the abundance with which the moon jelly releases is reproductive organisms.