Dictionary.net

• A small bony rod passing backwards from the ischiadic symphysis and supporting the ventral cloacal wall.

1920 - A dictionary of scientific terms.
By Henderson, I. F.; Henderson, W. D.

• [Greek] A small bony rod passing backwards from ischiadic symphysis and supporting ventral cloacal wall; hypogastroid; os cloacae.

1920 - A dictionary of scientific terms (6th edition)
By J.H. Kenneth