Skulls of holorhinal birds from dorsal:
<p>8. Great Bustard<br>
9. Chicken<br>
10. Cape Petrel<br></p>
11. Hawfinch
Unclear (initials ACC?)
1873
<i>Proceedings of the Zoological Society of London</i> (<a rel="nofollow" class="external text" href="https://archive.org/details/proceedingsofgen73zool">vol. 1873</a>, <a rel="nofollow" class="external text" href="https://archive.org/stream/proceedingsofgen73zool#page/35/mode/1up">page 35</a>)