The gastropods are the largest and most successful class of mollusks, with 60,000-75,000 known living species comprising the snails and slugs as well as a vast number of marine and freshwater species. While the best-known gastropods are terrestrial, more than two-thirds of all species live in a marine environment. Marine gastropods include herbivores, detritus feeders, carnivores and a few ciliary feeders, in which the radula is reduced or absent. The radula is usually adapted to the food that a species eats. The simplest gastropods are the limpets and abalones, both herbivores that use their hard radula to rasp at seaweeds on rocks.

 

Diagram Created By: Adrienne L

 

Photo Credit: http://en.wikipedia.org/wiki/Image:Snail1web.jpg