What is "gallinules"

Usage examples of "gallinules".

But if we bring it off - I say If we bring it off, Stephen,' said Jack clapping his hand to the wooden table-leg, 'then you and Martin shall have your bellyful of gallinules, red, white and blue: aye, and of double-headed eagles, too, both in the Red Sea and here when we re-embark, that I promise you.