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-continue>
    <alllinks galcontinue="Bassam_Dally|1370" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1371" ns="0" title="Journal Articles" />
      <page pageid="2124" ns="0" title="Mark D. McDonnell" />
      <page pageid="4377" ns="0" title="Alex J. Grant" />
      <page pageid="4378" ns="0" title="INGMAR LAND" />
      <page pageid="4380" ns="0" title="KEN LEVER" />
      <page pageid="4662" ns="0" title="Mehdi Miri" />
      <page pageid="4663" ns="0" title="Davood Fathi" />
      <page pageid="4664" ns="0" title="Mohsen Heidari" />
      <page pageid="4773" ns="0" title="Link budget to Mars" />
    </pages>
  </query>
</api>