_Myxomycetes_ signifying “slime-_fungi_,” while _Mycetozoa_ means “fungus-_animals_.” These remarkable organisms, of which over 180 species are found in the British Isles, begin life as tiny wind-borne spores. Under suitable conditions of moisture and heat, the spore swells, its wall cracks, and the contents--a tiny globule of protoplasm--creep out, develop a little tail or _flagellum_, which by lashing about propels the pear-shaped _swarm-cell_ through the drop of water in which it began life. The organism feeds by catching bacteria and other minute particles of organic matter, which are conveyed into the interior of the little mass of protoplasm and digested. The swarm-cells increase in number by division, and ultimately unite in pairs to form a _plasmodium_, which may, by union with other plasmodia, eventually attain a quite large size. In this naked protoplasmic mass a very remarkable rhythmic movement is set up, the granular protoplasm of the interior streaming rapidly along certain channels for about 1-1/2 minutes, when the motion is reversed and it streams in the opposite direction. The whole mass now creeps about in moist places, usually in the form of a network of branching veins, feeding as it goes, usually on dead vegetable matter. When fully developed the plasmodium creeps out into some more open spot and transforms itself into masses of spores enclosed in spore-cases, which vary much in different genera as regards size, shape, and colour, and are often borne on delicate stalks. When ripe, the spore-cases, or _sporangia_, open, and the spores are liberated into the air to be dispersed by wind and eventually to begin growth on their own [Illustration: FIG. 26.--A MYXOMYCETE (COMATRICHA TYPHOIDES) IN FRUIT. _a_, Natural size; _b_, enlarged.] account. This story partakes about equally of incidents characteristic of the life-history of the lower animals and of the lower plants. The fruiting stage and the wind dispersal of the spores recall the arrangements familiar in the Fungi, and are not matched in any section of the animal kingdom; while the creeping plasmodium, devouring food as it goes, is entirely suggestive of animal life, and is not paralleled anywhere in the vegetable kingdom. There is no reason to look on the Mycetozoa as a group of animals which have taken on certain plant-like characters, any more than as a group of plants which have evolved certain animal characteristics: we appear to see in them a very ancient group which has come down to us from a time when plants and animals, as we know them, had not yet become differentiated.