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
Cooking weights and measures Note that measurements in this section are in imperial units. Traditional British measures distinguish between weight and volume. American cooks using British recipes, and vice versa, need to be careful with pints and fluid ounces. A US pint is 473 mL, while a UK pint is 568 mL, about 20% larger. A US fluid ounce is of a US pint (29.6 mL); a UK fluid ounce is UK pint (28.4 mL). This makes an Imperial pint equivalent to 19.2 US fluid ounces. On a larger scale, perhaps for institutional cookery, an Imperial gallon is eight Imperial pints (160 imp fl