gills


the openings on the side of the tadpole's head that allow it to breathe; underwater lungs

 



Source
http://www.google.com/imgres?q=tadpole+gills&um=1&hl=en&client=firefox-a&hs=FjO&rls=org.mozilla:en-US:official&biw=1165&bih=606&tbm=isch&tbnid=UwqtZwuF0jwm1M:&imgrefurl=http://www.kiddyhouse.com/Themes/frogs/&docid=3RT33dpamsZrVM&w=166&h=89&ei=5q1yToyaCaTj0QH9yaywCg&zoom=1&iact=rc&dur=715&page=1&tbnh=71&tbnw=132&start=0&ndsp=21&ved=1t:429,r:7,s:0&tx=44&ty=41