different, and have naturally been supposed at first to have nothing to do with each other. Thus some of the little "coralline polyps" and other most beautiful little marine flower-like polyps attached to rocks, weeds, and shells in the sea reproduce by budding and division. But after a period of such growth and such budding they produce on their stalks--jelly-fish! These jelly-fish are budded and thrown off by them, as glass-like swimming bells, which lead an independent life, seize prey, nourish themselves, and grow to a size varying from that of a sixpence to that of a cart-wheel. These "bells" are commonly known as "jelly-fish." They discharge thousands of egg-cells into the sea and fertilise them with sperms! From those fertilised eggs grow young polyps, which fix themselves to rocks or weeds, and grow up to bud and multiply by fission, and eventually to produce again by fission a generation of jelly-fishes! Such a marvellous history of alternating modes of reproduction has been discovered, and described in greatest microscopic detail and with most ample pictorial representations of all the minutest structures of the organisms studied, not only in many marine polyps, but also in the case of many parasitic worms, such as the tape worms and the liver-flukes. Some of the most fascinating cases, on account of the beauty of the little creatures concerned, are found amongst the surface-swimming Ascidians of the sea--the glass-like Salps. But our common ferns and mosses also show this same alternation of sexual and sexless generations, the two generations differing greatly in size, form, and structure from one another, whilst the whole story of "flowers" and their structure is bound up with a wonderful "telescoping" or rolling of the two generations (sexless and sexual) into one plant!