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).
In amphibians, gills develop as larval organs of aquatic respiration, or in the form of external gills (caudate amphibians) or external and internal gills (acaudal amphibians). In some caudate amphibians, the external gills remain throughout life.n the process of animal evolution, gills first appear in annelid worms, in the form of simple, pectinate, or bipinnate plates and simple or branched filaments. They are located on the lateral motor appendages (in freely moving forms) or at the head end of the body (in those living in tubes).