Internally they are found to consist of a lamina twisted upon itself, and externally they generally exhibit a tortuous structure, produced, before the cloaca was reached, by the spiral valve of a compressed small intestine (as in skates, sharks and dog-fishes); the surface shows also vascular impressions and corrugations due to the same cause.
Among its manufactures are agricultural machinery (especially seeding machines) and tools, automobiles, pianos, lawn-mowers, roller-skates, foundry and machine-shop products, furniture, burial caskets, and flour.
They discussed their options—snowshoeing and cross country skiing—but decided to try out the ice skates that they had purchased for one another for Christmas.
The saw-fishes, Pristidae, the electrical rays, Torpedinae, and ordinary rays and skates, are also found in considerable numbers.
Skates made of bones have been dug up in this district.