Cycloid scales cover these teleost fish (rohu). The skin of most fishes are covered with scales. Scales vary enormously in size, shape, structure, and extent, ranging from strong and rigid armour plates in fishes such as shrimpfishes and boxfishes, to microscopic or absent in fishes such as eels and anglerfishes.The morphology of a scale can be used to identify the species of fish it came from.Cartilaginous fishes (sharks and rays) are covered with placoid scales. Most bony fishes are covered with the cycloid scales of salmon and carp, or the ctenoid scales of perch, or the ganoid scales of sturgeons and gars.Some species are covered instead by scutes, and others have no outer covering on the skin.ost bony fishes are covered with the cycloid scales of salmon and carp, or the ctenoid scales of perch, or the ganoid scales of sturgeons and gars. Some species are covered instead by scutes, and others have no outer covering on the skin.
definition : hydrometer. A hydrometer or areometer is an instrument that measures the specific gravity (relative density) of liquidsâthe ratio of the density of the liquid to the density of water. A hydrometer is usually made of glass, and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright.
If you suspect that the battery has a bad cell or two, you can buy a hydrometer from any FLAPS. This simple device checks the specific gravity of the battery electrolyte in each cell. A bad cell can cause the generator/alternator to overcharge the other cells which will trigger the generator light in the speedo.