n. (Zool.) Any one of numerous species of large cartilaginous ganoid fishes belonging to Acipenser and allied genera of the family Acipenseridæ. They run up rivers to spawn, and are common on the coasts and in the large rivers and lakes of North America, Europe, and Asia. Caviare is prepared from the roe, and isinglass from the air bladder. The common North American species are Acipenser sturio of the Atlantic coast region, a. transmountanous of the Pacific coast, anda. rubicundus of the Mississippi River and its tributaries. In Europe, the common species is Acipenser sturio, and other well-known species are the sterlet and the huso. The sturgeons are included in the order Chondrostei. Their body is partially covered by five rows of large, carinated, bony plates, of which one row runs along the back. The tail is heterocercal. The toothless and protrusile mouth is beneath the head, and has four barbels in front. Shovel-nosed sturgeon. (Zool.) See Shovelnose (d).