Jellyfish is the common name of a sea animal which, when cast up on the sand of the beach, seems only a mass of jelly. The commonest variety, that found on the New England coast, consists of a circular disk of jelly, called the umbrella. often fringed with long tentacles and from the center of which hang the feeding organs. By alternately contracting and expanding this disc the jellyfish moves freely about in the water. From the time it is hatched from the egg the jellyfish requires two years to mature, going through several interesting stages of development. Some forms of jellyfish are of almost unbelievable beauty.