wear your heart on your sleeve. to make your feelings and opinions obvious to other people John's always worn his heart on his sleeve, so there's no doubt who he'll be supporting. See also: heart, on, sleeve, wear. Related vocabulary: wear something on your sleeve.
In many bivalves and snails, and in cephalopods, part of the mantle is modified into a siphon, which can be used to pump water through the mantle cavity for respiration, feeding and/or jet propulsion. Freshwater and marine mollusks have gills (called ctenidia) for respiration, located in the mantle cavity. In most bivalves, these are enlarged and serve to trap food particles as well (Morton 1983).
Mollusks also have a special feature called a radula. Their radula is a sharp tongue-like body part that is used to scrape food off of hard surfaces and push it into their mouths. Mollusks can be found all over the world, on land and in the water. Depending on the animal, they can be found in either freshwater or saltwater. Clams can live in both freshwater and saltwater.