What I was trying to do was to run X11 applications from my linux box on my Mac. Here's the docs on how to do it:
The problem was that I was getting an error like this:
X11 connection rejected because of wrong authentication.
X connection to localhost:12.0 broken (explicit kill or server shutdown).
Turns out I has a couple of things going on. First, I guess something in my /etc/ssh/sshrc file was causing problems on my linux box. I moved that file out of the way and then got this error:
/usr/bin/xauth: error in locking authority file
I ran this command on the linux box:
xauth -b quit
Logged out, then back in. Problem solved. Now I can run my linux X apps remotely on my Mac. Pretty cool.