The free screensaver Jellyfish Curious Creatures was created by RateMyScreensaver.com and contains 27 high resolution images of Jellyfish. Jellyfish are marine invertebrates belonging to the Scyphozoan class, and in turn the phylum Cnidaria. The body of an adult jellyfish is composed of a bell-shaped, jelly producing substance enclosing its internal structure, from which the creatureТ‘s tentacles are suspended. Each tentacle is covered with stinging cells (cnidocytes) that can sting or kill other animals: most jellyfish use them to secure prey or as a defense mechanism. Others, such as Rhizostomae, do not have tentacles at all. To compensate for its lack of basic sensory organs and a brain, the jellyfish exploits its nervous system and rhopalia to perceive stimuli, such as light or odor, and orchestrate expedient responses. In its adult form, it is composed of 94-98% water and can be found in every ocean in the world. Most jellyfish are passive drifters that feed on small fish and zooplankton that become caught in their tentacles. Jellyfish have an incomplete digestive system, meaning that the same orifice is used for both food intake and waste expulsion. They are made up of a layer of epidermis, gastrodermis, and a thick layer called mesoglea that actually produces a main part of jelly and it separates the epidermis from the gastrodermis. Screensaver Picture Count: 27 Screensaver Type: Slideshow Credit: All images in this screensaver fall under one of the following licenses: Creative Commons, Attribution ShareAlike 2.0, public domain, GNU Free Documentation License.