The Ganoids 19 
ing smaller streams to spawn. Other sturgeons are marine, 
ascending fresh waters only for a moderate distance in the 
spawning season. They range in length from 24 to 30 feet. 
All are used as food, although the flesh is rather coarse 
and beefy. From their large size and abundance they possess 
great economic value. The eggs of some species are prepared 
as caviar. 
The sturgeons are sluggish, clumsy, bottom-feeding fish. 
The mouth, underneath the long snout, is very protractile, 
sucker-like, and without teeth. Before it on the under side 
of the snout are four long feelers. Ordinarily the sturgeon feeds 
on mud and snails with other small creatures, but I have seen 
Fig. 6.—Common Sturgeon, Acipenser sturio Mitchill. Potomac River. 
large numbers of Eulachon (Thaletchthys) in the stomach of 
the Columbia River sturgeon (Acipenser transmontanus). This 
fish and the Eulachon run in the Columbia at the same time, 
and the sucker-mouth of a large sturgeon will draw into it num- 
bers of small fishes who may be unsuspiciously engaged in 
depositing their spawn. In the spawning season in June these 
clumsy fishes will often leap wholly out of the water in their 
play. The sturgeons have a rough skin besides five series of 
bony plates which change much with age and which in very 
old examples are sometimes lost or absorbed in the skin. The 
common sturgeon of the Atlantic on both shores is Actpenser 
sturto. Actpenser huso and numerous other species are found 
in Russia and Siberia. The great sturgeon of the Columbia 
is Acitpenser transmontanus, and the great sturgeon of Japan 
Actpenser kikuchi. Smaller species are found farther south, 
as in the Mediterranean and along the the Carolina coast. Other 
small species abound in rivers and lakes. Actpenser rubicundus 
is found throughout the Great Lake region and the Mississippi 
Valley, never entering the sea. It is four to six feet long, and 
at Sandusky, Ohio, in one season 14,000 sturgeons were taken 
