THE STURGEONS AND STURGEON INDUSTRIES. 
269 
roe,” for example. The darker discoidal area is the germinal area of the egg of the 
sturgeon, and is the point where development first manifests itself to tlie unaided eye 
through certain changes in its shape. 
The eggs of the hind above described should retain their globular form, like so many 
shot, and shoidd show no signs of adhering to each other. If the round area at one side 
of the eggs should appear distorted or broken, it is also a sign that the eggs are probably 
worthless for fertilization. 
Eggs with a round disk, if they flow freely from a slit cut through the walls of the 
abdomen of the recently caught living fish, may be fertilized without difficulty, provided 
a ripe male is at hand. Eggs which do not answer to the requirements given in this 
paragraph it is not worth while to waste time over. 
It frequently happens that running or ripe fishes are brought in which have a great 
abundance of loose eggs in the abdominal cavity, which are entirely worthless for pur- 
poses of fertilization. Upon examination, it will be found that in such cases the eggs 
either have the discoidal germinal area distorted and injured, or else many of the ova 
have had their thin covering or zona radiata ruptured, and the yolk has been crushed 
and has escaped as a slate-colored substance. This rupture and injury to the eggs is 
due to the entrance of water from the outside, through the oviducts and genito-urinary 
passages, into the body-cavity, the presence of the water causing the glairy, adhesive 
coating to set or harden, and with which all the ova are covered upon leaving the 
follicles in which they were matured. This hardening of the mucigen which covers 
the eggs, in the presence of water, and while still with the body of the mother fish, 
will cause the bursting of the egg-coverings if such fish do not get the chance to' dis- 
charge their eggs at once, or happen to be roughly handled in the boats, as the ova 
adhere in great masses, the breaking or crushing of which also ruptures the individual 
eggs of which they are composed. Such roes are of no service whatever as a source 
of supply for inirposes of artificial fertilization. Roes of this kind may be at once dis- 
tinguished by their sliminess and the slate colored appearance of the contents of the 
broken eggs. 
Another type of roes are those of the entirely spent fish, which has discharged all 
of its mature eggs. The roes of such fishes are no longer brown, and the leaflets of 
which they are formed are made up of very small pinkish or pale, and very young ova. 
Snch fishes may be distinguished by the flabby, collapsed, or shrunken abdomen, since 
the remnant of immature roe left behind in the body-cavity is hardly a tenth part of the 
volume of the ripe ovaries as seen in fishes with mature or “ hard roe.” The rem- 
nant of the roes of a fish which has only recently got rid of its burden of eggs looks 
ragged when the ovary is wetted and floated out with water ; this is due to the j)resence 
of the collapsed leaflets formed of the vascular and cellular tissue from which the ova 
have escaped. These leaflets of the roes are disposed transversely on either side of the 
mesentery, or thin membrane, which fastens the alimentary tract to the middle line of 
the dorsal wall of the body-cavity. 
While the nearly mature roes of the females are relatively of great size — greater in 
fact than any other viscus of the body — they are also usually dark in color, as may be 
gathered from the figure in Plate LI, showing the roe exposed. The color of the nearly 
mature or “ hard roe ” is also subject to some variation. Occasionally fishes are found 
in which the roe is quite pale, and hardly darker than the other viscera. This is due 
to the nearly complete absence of pigment granules in the yolk of the individual 
