Do sea urchins have an eye or eyes?

[jelbert320]

Teresa's Sea Urchin | Flickr - Photo Sharing!

 

[archman]

It's probably the periproct (anus). Some species can extend a large flexible one that looks like a creepy, bulbous eyeball.

 

[lindenbruce]

So they basically have a photo sensor like those used on security lights? Bruce

 

[lmorin]

Virtually all living organisms, at least among those that have been tested, have at least one eye. It may not "see" in the sense of detecting images, but it does detect light vs dark. It has greater functionality than a security light detector because it detects and uses information about different light intensities. Such an eye is also virtually always connected to or is actually part of a "circadian clock" mechanism that allows plants and animals to synchronize physiology and behavior to the prevailing photoperiod. Exceptions include animals that have evolved in light-less conditions such has cave fish or crickets. I have also heard that, after analyzing organic molecules in many water samples from the world's oceans, scientists concluded that the most common proteins in the water are those used in vision.

 

[cooperscuba]

SEA URCHINS USE WHOLE BODY AS EYE

This research suggests that urchins use their whole body as an eye.

The "eye" in the posted question is the periproctal cone, a structure commonly referred to as the urchin's "anus".

 

[TjRjn]

Shutterfly Kodak Gallery Customer Welcome Page | Kodak Gallery and Shutterfly

Here is a link to the photo. Photo number 18. It is not as clear as my blown up one but can get the idea across.

The link doesn't seem to work.

---------- Post Merged at 10:39 PM ---------- Previous Post was at 10:23 PM ----------

I have a pic of a sea urchin that I swear looks like it has an eye ball. I can't seem to get a pic posted right now but thought I would ask the question.

I've tried to link to a pic from my gallery here but it's not working. If you go to my pics you will see one of a Sea Urchin I took a few years back in Cambodia. If you look hard you can see purple spots which, at the time, I presumed were eyes. On reading the link below I see my assumption was wrong so not sure what the purple spots are now.

http://www.livescience.com/5970-body-sea-urchin-big-eye.html