We now come to the consideration of other species of fish that need entirely different treatment. Most of them are rarely cultivated on the purely artificial plan in consequence of peculiarities of their habits or of their ova. The fish of which we have already treated have eggs that are loose in the uterine sacs when ripe, and are comparatively free from mucous when emitted. The eggs of the trout adhere at first to whatever they touch, and those of the whitefish need a little agitation for a time; but these qualities do not interfere with their management in troughs or on screens. On the other hand the black bass, the carp and their cognate varieties have eggs that are either surrounded with a glutinous fluid or attach themselves at once and permanently to whatever they touch. Some of them can be rendered free by agitation of the water, which is readily effected by placing the open hand upon it with the fingers distended and moving it up and down. This keeps the eggs in motion while it does not bruise or crush them.

The species of which we shall now treat include the black bass, Oswego bass, strawberry bass, rock bass, white bass, pike perch, striped bass, yellow perch, pickerel, muscalonge, carp, catfish and goldfish. The eggs of the white perch, pike perch, carp and goldfish stick fast to whatever they touch on emission, and must be kept in motion for an hour to remove this tendency. Those of the fresh water bass, yellow perch, pickerel and muscallonge are surrounded with a glutinous matter coming out like long semi-transparent ribbons which may be attached from point to point like a spider's web A change of water is needed for these, but not so strong a current as for the eggs of trout and salmon. The eggs of the striped bass are free from the sticky or glutinous matter, but are about as adhesive as whitefish eggs and need agitation for nearly an hour.