Very similar to the other picture above, but for the Girl's bathroom. Notable how 'sexist' the thinking was when this was built in the 1930's: The guy's version of this was accessed from the boy's bathroom. The girl's version was accessed through the adjoining classroom. The thinking, I'm sure, was that the janitor would be male and couldn't go into the girl's bathroom easilly to work on stuff... Rumor had it that you could sneak in here and peep into the Girl's bathroom, Porky's-style...
