Moon jellyfish

This is the most common species in the world and can be identified by the four horseshoe-shaped gonads that can be seen through the top of the bell. 

Moon jellyfish are a species of jellyfish, known by the scientific name Aurelia aurita, and are found mostly in warm and tropical waters, near sea-coasts. They are also referred to by names such as moon jelly, saucer jelly, common sea jelly and even violet moon jellyfish. These jellyfish are capable of withstanding temperatures as low as -6 °C and as high as 31 °C. They are found in both inshore seas and oceans, as well as in brackish waters, exhibiting salt contents as low as 0.6%. Although local to Virginia's waters, they are found in oceans across the globe. In the Pacific Ocean, they range from Alaska to Southern California and in the Atlantic Ocean, they range from the Arctic to Mexico.

The venom of Aurelia is harmless for humans and this jellyfish can be touched (in China it is a popular dish) even though, like all jellyfish it is very delicate and contacts can damage it. 

The Moon Jellyfish offers several subspecies. It is really impossible though to tell them apart without taking samples of their DNA. The size ranges between 6 and 20 inches. They mainly feed on plankton and rely on currents for drifting as they have limited locomotion.