Porpoise
2 of the 6 encyclopedias on this shelf carry an entry for Porpoise. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
por'pus, a well known animal of the coasts and harbors. It has the appearance of a clumsy fish, but in reality it is a relative of the whale, manatee, and other cetaceans. Most of all, it resembles the dolphin, but it is smaller; it has a blunt nose, and a heavier build. The name is French, signifying pork-fish. The German name is sea-swine. Although the porpoise is a degenerate land animal, the skin is smooth and destitute of hair. The eye is small and shaped like that of a pig. All members of the family require to breathe at intervals, which they do by means of a single nostril situated in the top of the head. The operation is called blowing. The breathing of the whole family, and especially that of the grampus, a twenty foot porpoise of the North Atlantic, is so noticeable that seafaring people nickname a fleshy, short-winded person a grampus. To puff and blow like a porpoise is also a common colloquial expression. Porpoises go in schools like fish. Sometimes they swim in single file, at a distance suggesting a sea serpent . They gambol goodnaturedly about in the harbors to the great satisfaction of onlookers. Like the seal, the porpoise pursues fish. Vast numbers of herring and mackerel are devoured by schools of porpoises. The skin of the porpoise is an inch thick. It is sheared down to form leather. It makes the best leather shoestring known. The flesh is dark and strong. It was once an article of diet in England, and also in Europe,--but its use as an article of food is said to be confined now to the Eskimos. See Dolphin
Collier's New Encyclopedia (1921)
the Phocæna communis, and any species of the genus; loosely applied by sailors to any of the smaller cetaceans. The common porpoise, when full grown , attains a length of about five feet. The head is rounded in front, and the snout is not produced into a beak. The external surface is shining and hairless, dark gray or black on the upper parts, under pure white. It is gregarious in habit, and is often seen in small herds, frequenting the coasts rather than the open seas. It often ascends rivers. It is found on the coasts of Scandinavia, and ranges as far N. as Baffin Bay and as far W. as the coast of the United States. It feeds on fish, and was formerly esteemed as an article of food. Its only commercial value now is derived from the oil obtained from its blubber, and its skin, which is used for leather and shoe laces.
What Has Changed in the Last Century
Aiton's grouped the porpoise with "the whale, manatee, and other cetaceans" and called it "a degenerate land animal" — the land ancestry was a good guess, but manatees belong to a separate order, the Sirenia, and the grampus that Aiton's called "a twenty foot porpoise" is not a porpoise at all. Porpoises are now set apart from dolphins as their own family, the Phocoenidae, of seven or eight species; Collier's Phocaena communis of 1921 is now Phocoena phocoena, the harbour porpoise. Fossils found in Pakistan and molecular work in the 1990s tied all cetaceans to hoofed animals, with the hippopotamus as their nearest living relative. The oil and leather trade Collier's described is gone, replaced by protective law such as the US Marine Mammal Protection Act of 1972, and one member of the family, Mexico's vaquita, described only in 1958, is now down to single figures and close to extinction.
Written for this edition, 2026.