Jellyfish as you know they are crazy looking creatures that sting and roam the sea but did you know that jellyfish have no brain? Jellyfish not only have no brain but have no blood or heart.
These elegant creatures are actually quite simple they have three layers, the outer layer is called the epidermis. The middle layer is called the mesogelea: a elastic jelly like substance.finally the inner layer called the gastrotermis. As for seeing, smelling and responding to other stimuli they have An elementary nervous system. These are the tings that make up jellyfish.