underachiever
Contributor
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.
Do sea urchins have an eye or eyes?
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Like their relatives the sea stars, urchins have an internal skeleton made up of chalky plates called ossicles. Instead of these ossicles being scattered around the body, they are organized into a solid circular case called a "test". The test of a dry sea urchin shows several interesting features: It is divided into ten equal sections. Five of these contain tiny holes used to extend the tube feet through the test. These sections are called ambulacral areas. The other five sections are called interambulacral areas and do not have tube foot holes. (These sections alternate around the test.) Both areas contain small, raised bumps called tubercles which were the attachment points for the spines. On the top of the test (the aboral side) is a small hole called a periproct, which releases wastes as well as eggs from the body. There is also a set of five eye spots surrounding this top opening which cannot see images but are sensitive to light and shadows. A larger hole, called the peristome, is on the bottom (oral side) and is used to extend the mouth.underachiever:
OP
underachiever
Contributor
Can't get pic to load. I'll keep trying
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You probably have to post it somewhere else and link to it. A lot of the SB functionality - including the photo gallery - is down lately since the "upgrade". SB is moving again to new servers soon to fix the problems.
H2Andy
Contributor
they could be "eyes" but their "eyes" don't really see like ours. i belive they
only detect light, so they can tell if it's dark or light
i'm not sure if you could call them "eyes"
only detect light, so they can tell if it's dark or light
i'm not sure if you could call them "eyes"
OP
underachiever
Contributor
http://www.kodakgallery.com/Enhance.jsp?UAUTOLOGIN_ID=29969523210
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.
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.
An eye generally refers to a light sensitive structure that can focus an image to some degree. An eye spot is a light sensitive structure than can detect levels of, and changes in the level of light but not focus an image.
Diver Dennis
Contributor
Are you talking about something like this? I couldn't get into your photos without a password.
H2Andy
Contributor
drbill:
ah, ok... so i guess they'd be killed eye spots
jelbert320
New
My wife and I were snorkeling in Jamaica and came across a Sea urchin that looks like it has an eye ball also. My wife came across it and when she just about got carried into it with the tide, she snapped the following photo. Have never seen anything like it. Does look like an eye though.. Any thoughts?
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