|Limpet eating algae in the aquarium.|
Seriously, though, if you look closely, you can see the scraping "teeth" on the radula. Here's the photo, cropped and saturated:
|The radula is like a conveyor belt with sharp cutting blades.|
Limpets use a radula to scrape algae from rocks. The radula consists of evenly spaced horizontal rows of cusps or teeth on a supporting ribbon, each row comprising 2-6 cusps. Rows in some species number up to 200 or more.From Limpets and Relatives, by Tom Carefoot, UBC.
Much like a tongue, the radula rolls outward, then is brought back with its load of algae, which then passes into the esophagus.
|Cross-section of a limpet mouth. (Limpets and Relatives)|
Sometimes, when the light is right, I can see tiny trails on the inside of the glass wall of the aquarium; limpet trails, where they've cleaned off the algae. They remind me of the snail trails in the algae on my old fence.
|Snails are bigger, and hungrier; their trails are easy to see.|