You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query>
    <pages>
      <page ns="0" title="Byrd Polar and Climate Change Research Center, The Ohio State University" missing="" />
      <page ns="0" title="Fa-cogs" missing="" />
      <page pageid="61" ns="0" title="Lamont-Doherty Core Repository Sediment Cores and Dredges" />
      <page pageid="93" ns="0" title="Lamont-Doherty Earth Observatory" />
      <page pageid="74" ns="0" title="Polar Rock Repository" />
    </pages>
  </query>
</api>