Bones referring to money

I was looking through the body part phrase section and I think you forgot one that im curious as to where it came from... bones referring to money....as in "that'll be 50 bones, pay up sucka" haha, for real though, where did it come from?

"Bone" for dollar goes back to 1896. But I haven't found why. From "Dictionary of American Regional English," Volume 1 by Frederic G. Cassidy (1985, Belknap Press of Harvard University Press, Cambridge, Mass., and London, England). Page 328.