It looks, Google has dropped the option to search within the directory from its Google Directory. If you visit the Google Directory today, the only search box you will see is a "Google search" box.
Whereas, until now it was a "Search Directory" button, but that is gone now. Google is even missing the search within directory feature on the inside pages of the Google Directory.
Here're before and after pictures:
[tags]Google Directory,Directory Search,Search Option[/tags]