AClPENSEli STUKIO. 409 



than long-, but become longer after the seventh, and the keel is then sharper, 

 and ends in a point. 



There are three shields behind the dorsal fin, two side by side, and the third, 

 which is oval, is behind them. There are forty-one lateral shields, which have a 

 lozenge shape, with serrated margins, and are transversely keeled. There are 

 ten ventral shields ; posteriorly they become somewhat larger, and more pointed 

 at the ends. Two shields, similar to the ventral series, are formed between the 

 ventral and anal fins. There is one very long and slender shield behind the 

 anal fin. 



The whole of the skin is covered with rough star-shaped scales, which vary 

 in size. On the throat they are quadrate or lozenge-shaped, and closely packed 

 together, so as to pi-esent the aspect of a tesselated pavement, though Heckel and 

 Kner compare them to the ganoid scales of the American Bony Pike [Lepiilosteu.s) 



The pectoral fin is as long as the body is high ; the height of the dorsal and 

 anal lins is equal. Both lobe-; of the caudal fin are pointed, but the upper 

 lobe is g-reatly elongated, and is much longer than the head. 



Acipenser sturio (Linn.eus). — The Sturgeon. 



The Sturgeon which is commonly taken in British rivei's, is known in 

 France as I'Estiirgcon,, though often called by fishermen I'Estiiouii. In Ger- 

 many the popular name is Star, and in Scandinavia Storge, or Sforji'r. In 

 Italy it is Storioue coiiiiimne. 



It is very widely distributed, and frequents the whole Atlantic coast of 

 North America, as well as the Atlantic coast of Europe. From this distribu- 

 tion it is known to the Russians as the Western Sturgeon, to distinguish it 

 from the Eastern Sturg"eon [A. guldenstddtii). It is absent from the Caspian, 

 and is not common in the Black Sea, from which it ascends some of the rivers, 

 though not recorded by Heckel and Kner in the Danube. 



According to Canestrini, it enters most of the rivers of Italy in March, 

 April, and May, and is more common in the river Po than the other 

 Sturgeons of the Adriatic. Steindachner found it during the spring months, 

 in the Spanish peninsula, in the Douro and Tagus. It is common in all the 

 great rivers of France, the Rhone, Garonne, Loire, and Seine. It ascends the 

 Rhine, and has been taken at Speyer, and, more rarely, at Basel. It is found 

 in all the rivers of North Germany, and goes up the Elbe into Bohemia, and 

 the Vistula into Galicia. In the Baltic it usually lives in deep water, from 

 which it rises in the spring to enter the German, Russian, and Scandinavian 

 rivers. In Britain it is only an irregular visitor, but is not rare in our fish- 

 markets, especially in London during the summer season. 



