Smaller, less important, less useful, but far more widely distributed is the chub-mackerel, or thimble-eyed mackerel, _Scomber japonicus_ (Houttuyn, 1782), usually known by the later name of _Scomber colias_ (Gmelin, 1788). In this species the air-bladder (absent in the common mackerel) is moderately developed. It very much resembles the true mackerel, but is of smaller size, less excellence as a food-fish, and keeps nearer to the shore. It may be usually distinguished by the presence of vague, dull-gray spots on the sides, where the true mackerel is lustrous silvery. This fish is common in the Mediterranean, along our Atlantic coast, on the coast of California, and everywhere in Japan. _Scomber antarcticus_ is the familiar mackerel of Australia. _Scomber loo_, silvery, with round black spots, is the common mackerel of the South Seas, locally known as _Ga_. _Scomber priscus_ is a fossil mackerel from the Eocene. _Auxis thazard_, the frigate mackerel, has the scales of the shoulders enlarged and somewhat coalescent, forming what is called a corselet. The species ranges widely through the seas of the world in great numbers, but very erratic, sometimes myriads reaching our Eastern coast, then none seen for years. It is more constant in its visits to Japan and Hawaii. Fossil species of _Auxis_ are found in the Miocene. The genus _Gymnosarda_ has the corselet as in _Auxis_, but the first dorsal fin is long, extending backward to the base of the second. Its two species, _Gymnosarda pelamis_, the Oceanic bonito, and _Gymnosarda alleterata_, the little tunny, are found in all warm seas, being especially abundant in the Mediterranean, about Hawaii and Japan. These are plump fish of moderate size, with very red and very oily flesh. Closely related to these is the great tunny, or Tuna (_Thunnus thynnus_) found in all warm seas and reaching at times a weight of 1500 pounds. These enormous fishes are much valued by anglers, a popular "Tuna Club" devoted to the sport of catching them with a hook having its headquarters at Avalon, on Santa Catalina Island, in California. They are good food, although the flesh of the large ones is very oily. The name horse-mackerel is often given to these monsters on the New England coast. In California, the Spanish name of tuna has become current among fisherman. Very similar to the tuna, but much smaller, is the Albacore (_Germo alalonga_). This reaches a weight of fifteen to thirty pounds, and is known by its very long, almost ribbon-like pectoral fins. This species is common in the Mediterranean, and about the Santa Barbara Islands, where it runs in great schools in March. The flesh of the albacore is of little value, unless, as in Japan, it is eaten raw. The Japanese shibi (_Germo germo_) is another large albacore, having the finlets bright yellow. It is found also at Hawaii.