Glyph and Origin

The glyph is a pair of curled forms, most often described as a crab's claws, though some readers see two clasping arms or a crab viewed from above; a further theory, genuinely debated rather than settled, traces the shape to a scarab beetle rendered in Egyptian Demotic script, since Egyptian sky lore placed a scarab rather than a crab in this stretch of the ecliptic. No ancient source confirms either account, and the derivation is best treated as unresolved by the paleographers who have studied the manuscripts.

The sign comes from the Babylonian zodiac fixed in the Hellenistic tradition, and the Greek myth attached to it the crab that Hera sent against Heracles during his fight with the Hydra, set among the stars for its trouble. The written mark is preserved chiefly through Byzantine copies of Greek horoscopes, the body of manuscripts catalogued by Otto Neugebauer and Henry Van Hoesen, and precession has since carried the tropical sign away from the constellation Cancer even as fifteenth and sixteenth century printed almanacs, in the line of Regiomontanus's pioneering Nuremberg press, were still fixing the glyph's standard typeset form for the first time in the history of the sign.