External gills usually contains muscle tissue, and may be moved by the animal as a free appendage, in order to stir up stagnant water. The stalk is lined by many thinly walled filaments (fimbriae), containing the majority of blood vessels used in gas exchange. Animals usually have one external gill originating on each gill arch (except the hyoid), which leads to there being three pairs of external gills in salamanders, and four in the gilled larvae of lungfish. External gills External gills are the gills of an animal, most typically an amphibian, that are exposed to the environment, rather than set inside
Pint cider may be sold by the imperial pint in perpetuity, and in public houses can only be sold in a third of a pint, two-thirds of a pint or multiples of half a pint, which must be served in stamped measured glasses or from government-stamped meters. Since the majority of countries in the world no longer use American or British imperial units, and most are non-English speaking, a "pint of beer" served in a tavern outside the United Kingdom and the United States may be measured by other standards. In Commonwealth countries it may be a British imperial pint of