A major part of the cleanup crew in my aquarium is made up of mudflat snails, Batillaria attramentaria, those invasive snails that crunch under our feet on the beaches of Boundary Bay. They probably would be invasive here, too, were it not that the big burrowing anemone eats all she can catch.
Most of them spend their time under the sand; when they venture out, usually to climb the walls scrubbing off the algae, all that can be seen of them are the shells and a hint of dark flesh at the lip. Rarely, one decides to look me in the eye (or camera lens). One of those curious ones was cleaning off a shell right beside the wall the other day.
|Striped face, striped tentacles. And a staring eye.|
These eyes can see some shapes, but they don't have a focussing lens, so things are blurred. And it seems that they don't see colours. Still, they can detect light and dark, day and night. For the rest, they don't have to chase the algae, nor could they dodge predators if they saw them; the eyes are good enough.
And they don't blink.
The three curves in the shade under the body almost look like crawly-type feet, but that effect is either from the pattern or the folding of the one fleshy foot.
|Full-face view. The eyes are at the base of the tentacles, and bulge outward. The one on the right is barely visible from here.|
A couple of years ago, another snail consented to be photographed. I blogged about it here.
|Big foot, patterned in green and grey, folded.|
And doesn't this critter, if you ignore the shell, look like a cuttlefish? Well, except that the cuttlefish eyes are on the forehead. And the nose is really a mass of tentacles. And it changes colour. And ... Well, you'll see what I mean if you look at this Common cuttle, from the Monterrey Bay Aquarium. (It's copyrighted, so I can only provide you with the link.)