<i>Diplodocus</i> heads, pencil drawing. They are based on skull specimen USNM 2673, which is now <i>Galeamopus pabsti</i>.<br>
a) skull, b) classic rendering of the head with nostrils on top, c) with speculative trunk, d) modern depiction with nostrils low on the snout and a possible resonating chamber.
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CC BY 2.5
<span class="int-own-work" lang="en">Own work</span>