THE STURGEON TRIBE 2891 



the tail is completely surrounded by the fin rays, and the muzzle Js either short or 

 developed into a narrow beak of moderate length. There is some doubt as to the 

 exact number of species of sturgeons, as these fish vary considerably according to 

 their age, but it is probable that nearly twenty different kinds may be admitted. 

 Among the better-known forms one of the most esteemed is the sterlet (A. ruth- 

 venus], which, although rarely exceeding a yard in length, yields better-flavored 

 flesh and finer caviare than any of the others. It is characterized by its narrow, 

 pointed snout, and by the great number of bony plates on the sides of the body; 

 these varying from sixty to seventy. Common in the Black Sea and Caspian, as 

 well as in their influent rivers, the sterlet is likewise found in the Siberian rivers, 

 while it ascends the Danube as far as Vienna. In contrast to this species may be 

 noticed the giant sturgeon or hausen (S. huso], shown in our full-page illustration. 

 Having from forty to forty-five lateral bony plates, this species may be readily dis- 

 tinguished by the absence of shields on the muzzle, which is rather short and pointed. 

 It is found in the Black Sea, Caspian, Sea of Azov, and their tributaries, and occa- 

 sionally enters the Mediterranean. At one time this sturgeon was to be met with 

 in the Danube by thousands, among which specimens of upward of twenty-four feet 

 in length were by no means uncommon; but relentless slaughter has greatly reduced 

 not only their numbers but likewise their size, although even now fish of fiom 1,200 

 to 1,500 pounds weight are occasionally taken. These, however, are mere pygmies 

 to certain Russian examples, one of which is stated to have weighed 2,760 pounds, 

 and a second 3,200 pounds. Migratory in its habits, this sturgeon crowds into the 

 Russian rivers as the ice is breaking up, when many individuals are more or less 

 severely injured by being jammed against the floes. It appears that only full-grown 

 fish ascend some rivers, as no small ones are found in the Danube; but in the Volga 

 these sturgeon are stated to remain during the winter in a semitorpid condition. 

 Although extremely powerful, the hausen is an inactive and timid fish, fleeing even 

 from the diminutive sterlet, and passing much of its time on the mud at the river 

 bottom, but rising occasionally to swim near the surface. In diet it is both carniv- 

 orous and herbivorous, feeding on vegetable substances, other fish, especially vari- 

 ous kind of carp, and even water fowl. Its isinglass is inferior to that of the 

 common sturgeon. Rarely visiting the British coasts, where it is a "royal" fish, 

 the latter species has only from twenty-six to thirty-one lateral plates, and from 

 eleven to thirteen down the middle of the back; the muzzle being pointed, and about 

 equal to one-half the length of the head. It is a widely-distributed form, frequent- 

 ing the coasts of both sides of the Atlantic, but absent from the Caspian, although 

 found in the Black Sea. In Italy it ascends the rivers from March to May; and 

 while in that country it does not commonly exceed five or six feet in length, speci- 

 mens of upward of eighteen feet are on record. 



The four species of the genus Scaphirhynchus (which must not be 



^ confused with the toothless sturgeons) differ from the preceding genus 



by the production of the muzzle into a spatulate beak, by the narrow 



and depressed hinder portion of the tail being completely covered by the bony plates, 



as well as in the absence of spiracles, and by the fin rays not surrounding the 



extremity of the upper lobe of the tail, which terminates in a long filament. 



