thanks for answering. My question born from this:
a) Catasterismi, by pseudo-Eratosthenes.
"During the Renaissance, printing of Catasterismi, invariably attributed to Eratosthenes, began early, but the work was always overshadowed by Hyginus, the only other ancient repertory of catasterisms. Catasterismi was illustrated by woodcuts in the first illustrated edition by Erhard Ratdolt, (Venice 1482)".
Wikipedia:
http://en.wikipedia.org/wiki/Catasterismib) translate from Spanish into my particular English
11. CancerSeems like the goddess Hera who placed him in the firmament. Account in his Heraclia Paniasis a crab out of the lagoon in which Heracles fought the Hydra with his foot and bit him on his own, without assistance of others. Heracles, irritated, crushed it with his foot, and since then the crab achieved fame and was counted as one of the twelve signs of the Zodiac.
Some stars of this constellation are called donkeys. Dionysus was the god who raised them to heaven. Next to them is called Nativity. Here is her story: When the gods left for the war against the Giants, said that the god Dionysus, Hephaestus and satyrs climbed astride donkeys, when the Giants still had not spotted, the braying donkeys were being found a short distance, and the Giants ran off to hear the braying. In return for such action donkeys became part of the constellation Cancer, the area west.
Regards!