Twisting the cuttlefish

i-67a1b5ccf3b96b8868995c8ec03db787-common-cuttle-fish-book.jpg


The "common cuttle-fish." From Mysteries of the Ocean.


About three decades before On the Origin of Species by Means of Natural Selection would forever change biological science, the aspiring young naturalists Pierre-Stanislas Meyranx and Laurencet submitted a paper on mollusks to France's prestigious Academie des Sciences. For weeks they waited for a patron from within the scientific elite to recognize their work, but no response came. Ultimately they decided to take the more direct route of having the paper examined by a commission, and in 1830 the naturalists Pierre-Andre Latreille and Geoffroy Saint-Hilaire were assigned to review it.

Had the mollusk memoir been given to other members of the academy it might have sunk into total obscurity. (And, truthfully, we only know of its existence as it is still lost.) It did not present anything that was set to rock the scientific establishment, but Geoffroy embellished it so that it did. Geoffroy, you see, had been involved in a scientific debate with his countryman colleague Georges Cuvier over nothing less than the philosophy of natural science. Cuvier preferred to think in terms of adaptation and function (even though he eschewed evolution) with Geoffroy stressed common anatomical groundplans and the way the same form was represented in slightly different ways throughout the animal kingdom.

Meyranx and Laurencet's paper played right into Geoffroy's hands. Even though they had not intended on refuting Cuvier, the naturalists proposed that mollusks shared an underlying body plan with vertebrates; mollusks were just twisted so that their "neck" was attached near their "buttocks." Thus mollusks were built upon the same anatomical groundplan as vertebrates, just slightly contorted.

This fit easily into Geoffroy's view of nature. It was the similarities of form, not differences of function, that mattered most, and he cast Cuvier's work on mollusks as conservative and stodgy. Natural science was changing and Geoffroy felt he represented its new direction.

Meyranx and Laurencet were horrified. They wrote to Cuvier assuring him that Geoffroy did not speak for them, but Cuvier was focused on his true intellectual adversary. During the next meeting of the Academie Cuvier criticized Geoffroy's scientific sloppiness. Geoffroy did not adequately define his terms, Cuvier charged, so how could anyone profitably discuss Geoffroy's ideas about form? More than that, the idea that a mollusk was just a twisted version of a vertebrate did not hold when looked at in detail. Geoffroy seemed to be wrong on every point.

Geoffroy, of course, responded, and the public debate dragged on for weeks. Cuvier would hammer away at the minute details of hyoid bones while Geoffroy would change from one topic to the next to keep his opponent on his toes. Strangely, though, for all the press the confrontations received the debates were not very scientifically profitable.

Even though the presentations of each scientist were well-attended and generated a lot of gossip, both Geoffroy and Cuvier were arguing past each other. They were set in their opinions and could make no progress. Ultimately they both let the argument fizzle. The debate was publicized and many people came to see the savants square off, but the arguments seemed to generate more heat than light. It was a battle of scientific philosophies and personalities, where knowledge of the natural world was wielded like a weapon to support one view of nature and destroy the other. As such there was not much room for new ideas to take root in the middle ground.

More like this

Cuvier preferred to think in terms of adaptation and function [while] Geoffroy stressed common anatomical groundplans...

Indeed, it's hard now to see how these could possibly be opposing viewpoints.

So, are we inverted arthropods, or contorted molluscs?

By Bryce Adams (not verified) on 17 Jun 2009 #permalink

Ultimately they decided instead to take the more direct route of having the paper examined by a commission, and in 1830 the naturalists Pierre-Andre Latreille and Geoffroy Saint-Hilaire. ... And, truthfully, we only know of its existence as it is still lost.

But still, its tentacles reach out from its hidden lair to snatch unsuspecting verbs!

By Pierce R. Butler (not verified) on 18 Jun 2009 #permalink

Thank you, Pierce. I don't know how I missed it, but I can tell you why that sentence went unfinished. Just as I was writing it a kitten jumped from on top of the fish tank near the desk to my shoulder and screeched in my ear (translation: pet me now!). It was a slightly painful experience so when I put the little purring ball of fur and claws on the floor I thought I had already finished the sentence. Indeed, kittens do not help the writing process.

Trying to understand life by looking at the cuttlefish is like trying to learn English by reading Lovecraft (and interestingly enough, both include lots of tentacles).

One can hardly blame these biologists, lacking a modern knowledge of comparative embryology and evolutionary relationships, for coming up with ideas like the twisted-mollusc or inverted arthropod. Neither is a crazy idea when you think about some of the bizarre ways body forms actually ARE related to each other. Their failure was simply not following the relationship all the way back to more fundamental common ancestors (of which they were largely unaware). That's assuming we are correct now, and future biologists won't be LOLing at our peculiar ideas on the topic ;)