Unformatted text preview: -torsion: mantle rotates 180 degrees bringing anus over the mouth -univalve -freshwater snails evolved from terrestrial snails, so they still have to come to the surface to breathe air-marine nudibranches: no shell, benthic, feed on cnidarians and sponges-terrestrial gastropod example: slug: shell less, taste buds and primitive eyes, mucus used for attachment -abalome: opening on sides, low on food chain-bivalves – clams, etc. – 20000 species – sessile-lost radula, reduced head, mostly filter feeders, gills used for respiration and feeding, foot used to dig into sand/sediment, ability to filter the water of light pollution-tridacna – giant clams (5 feet), cultured for food-polyplacophora – chitons – 1000 species – -flattened, shell of 7-8 plates: hinged, attached to rocks, grazing on algae...
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- Fall '08
- cephlapods -calcareous spicules, harpoon -mobile trochophore, segmented -mantle purposes, cilia -some adults, -muscular foot purposes