Fresh sets of arms continue to be developed successively upon the little jelly fish, until the whole amount in number to twenty-five or thirty. 'And the body, originally about the size of a grain of sand, becomes a line, or the twelfth part of an inch in length.' Thus far there appears nothing particularly striking or improbable in the history of the Medusæ; the next stage, however, exhibits matter for our 'special wonder.' The young Acaleph now throws off its animal existence, and sinks into a plant or compound polype. The lower part of the body swells, and from thence, what may be termed a _stolen_, is thrown out. On the upper surface of the stolen one and even two buds are often formed. 'As the bud enlarges it becomes elongated, and bends itself downwards to reach the surface of the stone to which the elongated extremity adheres; after this the attached end is gradually separated from the body of the parent. When thus detached, a small opening presents itself at its upper end, its interior gradually becomes hollowed out, and cilia grow upon it, and tentacula begin to sprout around the mouth, exactly in the same manner as in the buds formed on the upper surface of the stolens.' Thus, from a single bud numberless other buds are formed, each being endowed with equally prolific powers. If the parent be cut in half transversely, the cut will close in, attach itself to some object, and produce stolens and buds! If cut longitudinally, and the cut edges be allowed to touch each other, they will again adhere, and exhibit no trace of their ever having been divided. If the cut edges of each division be not kept apart they will approximate and adhere together, and thus two separate animals will be produced, each gifted with the power of throwing out stolens and buds with the same prodigality as if they had never been disunited! How long this budding process of necessity continues we cannot tell. It may be only during the winter season. These creatures in their perfect condition are generally found crowding our seas during the summer months; most probably, therefore, as Sars and Steenstrup state, it is at the commencement of spring that they undergo the last portion of this 'transformation strange.' Still, this cannot be taken as a general rule. Dr. Reid, who for a period of two years kept colonies of Medusæ, and assiduously watched the various stages of their development, found that the larvæ of one colony, which was obtained in September 1845, did not split transversely into young Medusæ in the spring of 1846, as he expected them to do, but continued to produce stolens and buds abundantly.