In a message dated 97-06-26 12:55:57 EDT, tons@ccs.netside.com (Michael) writes: << > Here would be an example of a reversal: their ancestors would have had the > erect stance, and it would have been lost in their modern descendants after > the endothermy and the quadricameral heart evolved. > Monotremes are heterothermic. >> Hah. Yet another reversal, obviously.