FISHES. 553 
in all the great European rivers, and this species is in a fair way of 
disappearing altogether. 
The Common Sturgeon, Acigenser sterio (Fig. 364), abounds in 
the North Sea and the Mediterranean, and occasionally it appears in 
the Thames, as well as here and there on the British coasts ; in the 
Rhine, the Seine, the Loire, and the Gironde. It is usually from 
six to seven feet long, but has been known to attain the length of 
Fig. 364.—The Common Sturgeon (Acipenser sturio). 
nine or ten feet. Its general colour is yellow, with a white belly. It 
is rendered remarkable by the number and form of the osseous 
plates or scales, which cover the body like so many bucklers. Upon 
the back and belly are no less than twelve to fifteen of these rough 
bony plates, relieved by projections, which are pointed in the young, 
and are worn down with age. On each side is a row of thirty to 
thirty-five of these triangular ganoid plates, separated from each other 
by considerable intervals. The head is broad at the base, gradually 
contracting towards the point, and terminating in a conical muzzle. 
The mouth is large, and placed considerably behind the extremity of 
e 
