Axes3d vs axes3d matplotlib

I just finished a horrible install of scipy, numpy, and matplotlib on OSX Lion. For some reason, I can't do a:

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3d

Error output is:

Traceback (most recent call last):
  File "3dPlot.py", line 2, in <module>
    from mpl_toolkits.mplot3d import Axes3d
ImportError: cannot import name Axes3d

but I can do:

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import axes3d

Is there a different between Axes3d and axes3d, or is my file just named with a lowercase 'a' for some reason?