are noticing that there are a lot more jellyfish than before really define it but sadly we don't have systematic long term data to answer our questions if i thought. jellyfish don't have a brain or a heart. they swim by contract. ting ring shaped muscles to create an underling motion that propels them forward their jelly matter bodies are kept together by 2 thin layers called epidermis and gastro dermis inside jellyfish have an essentially hollow space which is their gastro vascular cavity prey is guided from the tentacles by arms through the stomach tube and into the interior. experts are discovering more and more of these animals remarkable skills the moon jellyfish or alien or rita is found in all the 7 seas and can form huge swarms gilly is especially worried by one mediterranean species the prologue to luca which glows in