If we suppose the circle divided, as in the Tomoye, to be a very ancient badge or device, dating from prehistoric man, then it is probably derived from a natural object. And this object was probably a ground-down transverse section across a whelk-shell, for if one makes such a section just above the mouth of the shell at right angles to its length, one gets two adjacent chambers of the spirally-coiled shell separated by an S-like partition, the resulting figure given by the slice across the shell being that of the "tomoye," with its paired, one-sided, cone-like constituents. Shells are amongst the chief ornaments used by prehistoric and modern savage man. Large ones are ground down to make armlets. The perception of the spiral as a decorative line is almost certainly due to the handling and grinding-down of snail shells, and, indeed, we find spirals and reversed spiral scrolls engraved on bone by the Pleistocene cave-men (see Fig. 29). [Illustration: FIG. 57.–Terra-cotta cone with a seven-armed sun-like figure engraving on it. Troy. (Schliemann.)] The Ægæan people of the Greek islands (of whom the Mykenæans are a part) copied a variety of forms of marine animals in their decorations of pottery, and, in fact, natural shapes were the basis of their decorative art. They simplified and "grammatized" their more nature-true designs into badges and symbols. [Illustration: FIG. 58.–Scalloped Shell Disk, from a mound near Nashville, Tennessee, showing in the centre a tetraskelion with four curved arms, about four inches in diameter, made of polished shell. (Peabody Museum.)]