periods of Egyptian history:</p><ol><li><p>the early predynastic period (circa 4000 BC);</p></li>
<li><p>the late predynastic period (circa 3300 BC);</p></li>
<li><p>the 12th and 13th dynasties (circa 1850 BC);</p></li>
<li><p>the Ptolemiac period (circa 200 BC);</p></li>
<li><p>the Roman period (circa 150 AD).</p></li>
</ol><p>The question is whether the measurements change over time.  Non-constant
measurements of the skulls over time would indicate interbreeding with
immigrant populations.</p>
<p>Note tha