Platypus Ornithorhyncus anatinus.
The male has poisonous spurs on its hind legs. One nerd point for me. :-)
We have a layout problem, which I'm not sure how to fix (as in, I'm not sure what it should look like; this isn't a coding problem): as this page currently displays, subclasses look as though they are part of orders, instead of the other way around.
Moved to talk:
"(Linnaeus named the order mammals for their breasts because he wanted to encourage women to breast-feed their infants.)"
Re name "mammalia": I think I got this from Stephen Jay Gould. Not patriarchal hegemony at all--breast-feeding one's own infant rather than hiring a wet-nurse (or, nowadays, using formula) doesn't map particularly well onto patriarchy, though it does have class elements. I'll see if I can find documentation on this. --Vicki Rosenzweig
Okay, I did a bit of googling. At http://biology.uindy.edu/langdon/HUMANSTRATEGY01/24birth.htm I found "Lactation and suckling are perhaps the only behaviors found in all mammals and are definitive of the order. (Linnaeus, who created the name Mammalia, was a supporter of women breast-feeding their own children instead of hiring nursemaids; hence his choice of nipples, rather than hair or the placenta to define the order.)" That's a bio textbook; not conclusive, perhaps, but I think a neutral source. Vicki Rosenzweig again