Hydra, also called the serpent of Lerna, was a beast with the body of a hound and 100 serpentine heads. As if this weren't bad enough, it also had poisonous breath and it was so hideous that it caused most people to die of fear from simply seeing it. One of Hercules' great tasks was to kill this monster. When he started to fight it, he discovered that every time he cut off one of the heads, three grew back in place of it. Seeing this was getting him nowhere, he had his charioteer, Iolus, burn the stump after each time he cut off a head, which prevented the unfortunate regeneration. The last head was immortal, however, so after cutting it off, they trapped it under a rock.

The another Hydra, one of the simplest multicellular organisms, is a member of the phylum Cnidaria, and the class Hydrozoa. The Hydra is a freshwater animal. The body is a thin cylinder with several tentacles extending from the mouth. (Five to seven tentacles are typical.) Hydras can be many different colors, including tan, grey, green, and brown. They are typically 6 to 13 millimeters long, but are capable of stretching out or contracting.

The Hydra reproduces by a method known as budding. Sometimes a small growth will appear on the adult hydra's body, and will soon grow tentacles and break away. The new hydra that is formed can live without the adult hydra once it has broken off. They can also produce sperm and eggs inside of their body wall. The sperm fertilizes the egg and is released from the adult hydra. A layer forms to protect the egg from damage. Once the egg has developed, a hydra hatches from the capsule.

There is no circulatory system in the Hydra. As the body is only two cell layers thick, cells have easy access to the things it needs. As the Hydra moves through the water, the cells interact with the environment, transfering oxygen and carbon dioxide.

The Hydra has two layers of cells. The function of the outer layer of the Hydra, the epidermis, is for protection. The inner layer, the gastrodermis, is the digestive layer. There are two types of cells on the inner layer. The first, gland cells, secrete enzymes that allow of the Hydra to digest it's food. They can also secrete gas bubbles that enable the Hydra to float to the surface of the water. The second type of cells, nutritive cells, have flagella on them that mixes the food as it is being processed. In addition, the nutritive cells have pseudopods that collect digested food.

The Hydra does not have a central nervous system either. Instead, it has what is known as a nerve net. In between the inner and outer cell layer is the mesoglea, which contains nerves. Synapses are carried through the nerve net from sensory receptors located on the epidermal layer. These synapses control muscle contractions, allowing the Hydra to expand, contract, and move.

Computer system called Hydra is simmilar, it consists of computers connecter trought network interconnected into one big strong hardware platform that contains no weakneses in comparison with one supercomputer. Hydra consists of Hydra-head, it's the strongest and fastest computer in Hydra network, and Hydra-nodes - these computers can take up the Hydra-head function if Hydra head fails or disconnects.

Some pictures of hydra system:

Rack with Hydra-nodes
Hydra-Head motherboard
Hydra-Brouter, special computer for Hydra-Network optimalization
Hydra-System Monitoring
Windows XP running on Hydra system