Genus Acipenser. (Linn.)
In addition to the characters already detailed, the Sturgeons have the snout more or less prolonged and pointed, and furnished, on its under surface, with several cirri or beards, which hang down in front of the tubular, protrusile mouth. The fins are rather small, and, with the exception of the pectorals, are all placed far behind. The flesh in general is wholesome and agreeable; the roe, which is of considerable bulk, is made into a substance called caviare, held in high estimation in some parts of Europe; isinglass of the best quality, is made of the inner coats of the large and thickened air-bladder; and the skin is sometimes made into leather, or prepared as a substitute for window-glass. Hence these fishes are the subjects of important fisheries, especially in the east of Europe. The Russian fisheries, on the Caspian Sea, are very valuable; three species inhabit that great inland lake,—the Common Sturgeon (Acipenser sturio), the Great Sturgeon (A. huso), and the Sevruga (A. helops). The number of fishes taken in a single season is immense; of the first species named, three hundred thousand; of the second, one hundred and three thousand; of the third, one million three hundred thousand; are considered as the annual average. The products of isinglass, and caviare, exclusive of the flesh, which is preserved in various ways, and is a valuable article of merchandise, are alone worth more than 100,000l. per annum.
We have said that these fishes attain large dimensions; the Common Sturgeon, which occasionally ascends the rivers of this country, has
