Second Thoughts

http://commons.wikimedia.org/wiki/File:Stego-marsh-1896-US_geological_survey.png

Behold the mighty Dinosaur,
Famous in prehistoric lore,
Not only for his weight and strength
But for his intellectual length.
You will observe by these remains
The creature had two sets of brains —
One in his head (the usual place),
The other at his spinal base.
Thus he could reason a priori
As well as a posteriori.
No problem bothered him a bit:
He made both head and tail of it.
So wise he was, so wise and solemn,
Each thought filled just a spinal column.
If one brain found the pressure strong
It passed a few ideas along;
If something slipped his forward mind
‘Twas rescued by the one behind;
And if in error he was caught
He had a saving afterthought.
As he thought twice before he spoke
He had no judgments to revoke;
For he could think, without congestion,
Upon both sides of every question.

Oh, gaze upon this model beast,
Defunct ten million years at least.

— Bert Leston Taylor, A Line-O’-Verse or Two, 1911