The crab, tortoise, and beetle, the creatures selected to represent Cancer, are similar in many respects. They are hard shelled, insignificant in appearance, and sluggish in their movements, and in this latter attribute would well typify the sun's apparent movement when it arrives in this constellation.
"If it is admitted," says Plunket, "that in Egyptian astronomy the beetle played the important part of marking as a constellation one of the quarters of the ecliptic circle, then the fact that extraordinary honour is paid in Egyptian symbolic art to this lowly and unattractive insect is explained."
Aratos called the constellation καρκίνος. Latinised it is found as "Carcinus," in the Alphonsine tables. In some Eastern zodiacs Cancer is represented by the figure of two asses, and some of the mediaeval astronomers represented it as a lobster or crayfish. In these similes we have, as in the case of the crab, tortoise, and beetle, slow-moving creatures used to represent the constellation, so that there is little doubt that this sign was meant to emphasise the apparent movement of the sun when it was in this part of the zodiac.
According to the Greek legend, this is the crab that seized the foot of Hercules when he was fighting with the Lernean Hydra. The hero crushed the reptile to pieces under his heel, but Juno in gratitude for the offered service, placed the crab in the heavens. Another legend relates that Bacchus, afflicted with insanity, betook himself to the temple of Jove. On the way thither he came to a great marsh, over which he was carried by an ass, one of two which happened to be near at the time. In return for this service, he transformed both creatures into stars. Still another story respecting these stars claims that they owe their place in the heavens to the fact that they were of service to the gods in their battle with the giants. Silenus and Bacchus rode them, and the loud braying of the asses frightened their enemies.
