--> present in?
--> what they are?
--> what happens ?
Present in: larval fish and in some amphibians like the mudpuppy
What they are: outgrowths of the integument in the pharygeal area that becomes inflitrated with blood capillaries and filamentous material--very thin, fluffy material--where exchange takes place
What happens: As the animal swims, oxygen moves into the gills and then into the blood capillaries. CO2 moves in the opposite direction