Dear David, Andrew, et al.,
I'll certainly make no claim to being a snailwatcher with Aydin's
keenness, but it appears at least one common non-stygian eastern US
land pulmonate snail lacks eyes. See <http://www.jaxshells.org/1002qq.htm>.
Harry
At 01:08 AM 8/28/2009, you wrote:
>Thanks, Andrew. It's encouraging to think of snails having more than
>rudimentary vision. I had only come across one webpage on this
>http://www.applesnail.net/content/anatomy/senses.php -- admittedly
>not a terrestrial snail example, but with reasonably recent references.
>
>Wouldn't the visual discrimination of a snail depend to a large
>extent on its nervous system outside the eyes themselves? Maybe
>there have been some experiments with snail neurons.
>
>Say, where's Aydin? He might have some experience with landsnails
>doing behaviors that seem odd to humans.
>
>David Kirsh
>Durham, NC
>
>-----Original Message-----
> >From: Andrew Grebneff <[log in to unmask]>
> >Sent: Aug 27, 2009 6:58 PM
> >To: [log in to unmask]
> >Subject: Re: [CONCH-L] further adventures of Eli and Milton
> >
> >> For a few seconds, their eyestalks intertwined, i.e. doubled
> back nearly 180 degrees around each the other's like intertwined
> pinkies. They then traveled separately but parallel for a while.
> >
> >Cute... they're in love!
> >
> >> Also, is there any simulation of what snails "see", just as
> there are simulations of what flies' compound eyes "see"?
> >
> >The old "mosaic image" idea is long dead. Arthropod compound eyesight
> >is excellent; each cell in the eye produces an image which overlaps
> >those of its neighbors, producing a flawless image... almost
> >wraparound in the case of eg dragonflies.
> >
> >I'd bet that the majority of snails have pretty good vision. It would
> >certainly be to their advantage. Their eyes are typically complex, and
> >even a pinhole camera (and therefore a lensless eye such as that of
> >nautilus) can give a decent image.
> >
> >--
> >Regards
> >Andrew Grebneff
> >Dunedin, New Zealand
> >Fossil preparator
> >Mollusc, Toyota & VW van fanatic
> >
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>
>"When you're chewing on life's gristle, DON'T grumble. Give a
>whistle!" --from Life of Brian
>
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