I once heard a lecturer describe a marine organism on the borderline between plant and animal. It spends most of its time attached to rocks, but during one phase of its life it develops a very simple brain, detaches from the rock, and moves to an area with more nutrients. Then it re-attaches and consumes its own brain. The lecturer likened it to a professor who had gotten tenure.
– Nancy Murphy, Bodies and Souls, or Spirited Bodies? (New York: Cambridge University Press, 2006), p. 58 – footnote 24
That ladies and gents is why you should read footnotes. By the way, this book is a fascinating argument for the non-existence of the soul. It’s worth the read if for no other reason than to understand physicalism.