Answer:
They represent the twins that the woman will bear.
Step-by-step explanation:
You must be referring to the Iroquois Creation Myth. Well, each Indian tribe had its own creation myth that was told from generation to generation until the arrival of Europeans. The myth of the Iroquois begins by telling that a great super spirit had a daughter who was pregnant. This great spirit ordered a giant tortoise to come out of the water, but to bring some slime in its shell.
When the tortoise hit the surface it was possible to see the arrows on the turtles back. That meant the twins the woman will carry.