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 all the various gallons with a new imperial gallon based on ten pounds of distilled water at (277.42 cubic inches), from which the current UK pint is derived. The various Canadian provinces continued to use the Queen Anne Winchester wine gallon as a basis for their pint until 1873, well after Britain adopted the imperial system in 1824. This made the Canadian pint compatible with the American pint, but after 1824 it was incompatible with the British pint. The traditional French "pinte" used in Lower Canada (Quebec) was twice the size of the traditional English "pint" used in Upper Canada