Popular Science Monthly/Volume 4/December 1873/Haeckel's Moners
THE moners are the simplest organisms we know of—we might even say, the simplest that can exist. In them, life is exhibited under the form that is best fitted to give us an idea of its essential characters, stripped of all secondary attributes. The first moner was discovered by the celebrated Prof. Häckel, of Jena, in 1864, and the number has gone on steadily increasing ever since. These discoveries have made a great stir in the scientific world, owing to their bearing on our theories of organization.
The moner which best typifies the entire class is the Protomyxa auratitiaca. This little creature, hardly visible to the naked eye, and, at most, as big as a small pin-head, is of a fine orange-red color, consists of a perfectly homogeneous and transparent mass of jelly, and offers the paradox of an organism without organs. Nor is this absence of organs merely apparent, or owing to the imperfection of our magnifying-glasses; it is real, and every thing about these little creatures goes to prove their perfect simplicity of structure. This gelatinous, homogeneous, contractile substance has been called sarcode, and also, but improperly, animal protoplasm.
2. The same sending forth its pseudopodes and embedding a foreign body in itself.
3. The same in process of reproduction, after having exuded its envelope, and split up into a number of spherical masses.
4. A young moner set free after the bursting of the envelope.
In repose, the moner is nearly spherical, and gives no sign of life. But soon this little ball flattens itself out, its mass expands in various directions, and these expansions, which have received the name of false feet, or pseudopodes, keep up a continual movement of protrusion and retraction. Sometimes the moner flows all in one direction, and this is its way of moving from place to place. When, in the course of this slow progress over the calcareous slime of the sea-bottom, the moner falls in with one of those microscopic organisms called diatoms, it embeds it in its own body; the alimentary substances contained in the diatom are dissolved and assimilated, and the indigestible portions are left behind as the creature moves along. Thus, we have the curious phenomenon of a creature which feeds without mouth, without stomach, without apparatus of any kind, simply by incorporating into itself, as it moves, prey of every kind. In taking food, the animal appears to be passive, its seizing on its prey being a mere incident of its moving about.
In this way, the moner attains by degrees a certain size, and then stops growing and moving. It then becomes a little ball, exudes from its surface a colorless, homogeneous matter which hardens, forming a protecting envelope for the inclosed mass. Then, a very singular phenomenon occurs: by an act entirely spontaneous, the inclosed mass breaks up into a certain number of parts, which soon become independent, constituting so many little spherical masses lying side by side within the common envelope. The original moner then exists no more; it has reproduced itself by dividing itself up, without any intermediary, into these new individuals, its progeny. Each young moner is a determinate part of the mother-animal, and, leaving out of consideration what she exuded to form the envelope, all the rest of her substance is exempted from death, and is now to begin a new life, which in turn will pass through the series of transformations already described. The envelope will soon break up and set at liberty the young moners, which, from the first, resemble the mother-animal.
At the grade of extreme simplification of life presented to us in the moner, we have organization reduced to pure sarcode, and life manifesting itself by nutrition, reproduction, and contractility, each reduced to its barely essential function nutrition reduced to mere assimilation, reproduction to a spontaneous fission into a group of young (fissiparity), and contractility to the slow, diffusive movements of the pseudopodes.
Moners are mostly inhabitants of the sea. Some of them live at inconsiderable depths; but there is one, the Bathybius Häckelii, which lives at the enormous depth of 12,000 feet, and sometimes even of more than 24,000 feet. There is only one fresh-water moner.
Many naturalists rank moners among animals, classing them as rhizopods. Häckel, who discovered them, regards them as the representatives of an entire category of beings intermediate between animals and plants, the protista, so called from protos (first), because, according to this author, they are the first representative of terrestrial life, from which all other forms of life are developed, on the modern theories of Darwinism.—La Nature.