GENUS ACIPENSER. 383 



The bulbus arteriosus has two rows of valves at its commencement, and a 

 third row at its termination. The large aorta extends in a channel on the 

 under side of the cartilaginous vertebral column. 



Giinther remarks that the geographical distribution of Sturgeons is nearly 

 identical with that of Salmon. They are scattered over the whole of the 

 northern regions of the earth. Some species are confined to fresh water, but 

 they mostly live in the sea, and go up the rivers into lakes. In some streams 

 they are found in incredible multitudes, and remain in them for months. 

 Towards winter they seek deep holes in the rivers, or more commonly the 

 mouths of rivers and inlets of the sea, where they crowd together and pass 

 the winter in a hybernatiug condition. According to Lepechin, they burrow 

 their heads into the mud, so that their tails stick up straight in the water like 

 a fence. Sturgeon are among the largest of freshwater fishes; and they 

 occasionally reach a length, in the larger species, of eighteen feet. They are 

 very voracious, and live chiefly on soft-bodied animals, worms, spawn, and 

 bottom-feeding fishes ; but many also take water-birds, which are swallowed 

 whole. Sturgeons increase very rapidly, but the numbers in the rivers of 

 western Europe have greatly diminished. Even in Hungary they were 

 formerly an important source of income to the fishermen, and were commonly 

 taken of seven or eight hundred pounds' weight, while occasionally fishes were 

 captured twice as heavy. Forty or fifty years ago it was rare to 'see a fish in 

 the Vienna market of less than one hundred pounds, and now only very small 

 ones are caught. The diminution in size is due partly to the capture of 

 spawning fishes, and partly to excessive fishing, which has reduced the value of 

 the fisheries, just as the Salmon fishing of the Tweed and other British 

 rivers was injured in former years. 



In Britain the Sturgeon is only an occasional visitor ; and by far the larger 

 number of individuals as well as species is found in the south-east of Russia. 

 Several species are North American, and are met with on the Pacific coast 

 and in California!! rivers, on the Atlantic coast, in the Mississippi, and in 

 some of the great lakes. Certain of the species are common to Europe and 

 the North American continent, while there is a peculiar genus limited to the 

 Mississippi and its tributaries, which has no spiracles, and has the tail com- 

 pletely enveloped in bony armour. 



Sturgeon fishing is earned on in different ways in summer and winter. In 

 autumn, the Sturgeons which hybernate bury their noses in the mud on the 

 bottom of a river. About January the fishermen assemble, and at a given 

 signal, get to work with poles upward of sixty feet long, each having six to 

 ten prongs at the end. Holes are made in the ice. This operation disturbs 

 the fishes, and this instrument put down through the holes often strikes one 



