WP replaces <

I am trying to document the more tag on my blog and I am reduced to writing it out as & lt;!−−more−−& gt;

But when I save and edit the page later, the & lt; and & gt; get replaced by < and >. Why does this happen and how do I make it stop?

I know there are spaces where they shouldn’t be, if I don’t have them there, they just get interpreted.