494 FISHES CHAP. 
our own coasts the capture of individuals 8 to 10 feet in length 
has been recorded. The great Russian Sturgeon (A. huso), which 
is common in the Black Sea, the Sea of Azov and the Caspian, 
and in the rivers flowing into them, is the largest of all the 
Sturgeons, individuals weighing 2760 and 3200 pounds having 
been captured. The Sterlet (A. ruthenus), similarly distributed 
and often ascending the Danube to Vienna, is much smaller, 
rarely exceeding a length of three feet. 
In Europe 4. sturio spawns about July, but in North 
America (Delaware river) during May. Small in size, the eggs 
are produced in enormous numbers, a single female, it is said, 
producing about 3,000,000 in one season. They are invested 
by a gelatinous sheath, so that they readily stick to one another 
Fia. 291.—Larval Acipenser ruthenus. a, Anus; 6, barbels; e, eye; g, gills; m, 
mouth, with teeth ; o/.0, olfactory organ; op, operculum ; pt.f, pectoral fin; sp, 
spiracle. x10. (From Kitchen Parker.) 
or to other objects, and, when deposited, they adhere in streaks 
or sheet-like masses to the bed of the river. The young are 
hatched very early, about the third or fourth day in A. sturio, 
and in the Sterlet between the ninth and twelfth, the length of 
the larva then varying from 7 to 10 mm. When they are a few 
days old the larvae closely resemble those of existing Holostei 
except that the small opercular folds leave the gills freely ex- 
posed (Fig. 291). A shallow pigmented groove in front of the 
mouth apparently represents the sucker of the young Amia and 
Lepidosteus. Although toothless in the adult, both the Sturgeon 
and Sterlet possess vestigial rudimentary, uncalcified, larval teeth, 
which in shape resemble the teeth of a Dog-Fish, consisting of a 
broad base and a sharp spine. 
The Sturgeon is a Fish of considerable economic importance. 
The flesh is an article of food, and from the ovaries of certain 
Russian and American species thousands of hundredweights of 
