Breathing through what?

Following lunch time conversation, which inevitably gravitates towards all things fecally related, I had to check upon the topic of "alternative" breathing strategies. To be able to breathe in water, you need two things: current and large surface area. And it seems some turtles, particularly one living fossil in australia, has just that, in its ass. It has evolved a pair of cloacal bursae lined with villose mucosa and connecting to the cloaca, fully capable of contracting. And it's not even alone in having evolved this particular ability: the dragonfly nymph can use its butt for both breathing and propulsion! For more information on butt-breathers, this article goes into more details...