Jellyfish system. Nematocysts, which deliver the sting, are located mostly on the tentacles; true jellyfish also have them around the mouth and stomach. Jellyfish do not need a respiratory system because sufficient oxygen diffuses through the epidermis. They have limited control over their movement, but can navigate with the pulsations of the bell-like body; some species are active swimmers most of the time, while others largely drift. The rhopalia contain rudimentary sense organs which are able to detect light, water-borne vibrations, odour and orientation. A loose network of nerves called a "nerve net" is located in the epidermis. Although traditionally thought
Jellyfish Lake the thickness of the sediment (at least 20 meters) and the rising sea level since the end of the last ice age. About 12,000 years ago, the sea level had risen to the point that sea water began to fill the Jellyfish Lake basin. Two species of scyphozoan jellyfish live in Jellyfish Lake, moon jellyfish ("Aurelia" sp.) and the golden jellyfish ("Mastigias" sp.). The golden jellyfish are most closely related to the spotted jellyfish ("Mastigias papua") that inhabit the nearby lagoons. They are similar to the spotted jellyfish in that they derive part of their nutrition from symbiotic algae (Zooxanthellae)