How did Ignosi proved that he was a rightful king?

Ignosi showed his uncle the tattoo on his midsection..... the tattoo that proved he was the son of his father.... the king.

"I am Ignosi, rightful king of the Kukuanas!"

Then with a single movement Umbopa slipped off his "moocha" or girdle, and stood naked before us.

"Look," he said; "what is this?" and he pointed to the picture of a great snake tattooed in blue round his middle, its tail disappearing into its open mouth just above where the thighs are set into the body.

Infadoos looked, his eyes starting nearly out of his head. Then he fell upon his knees.

"Koom! Koom!" he ejaculated; "it is my brother's son; it is the king."