2. The embryo within the egg, just before hatching. The embryo has been constricted off from the yolk-laden portion of the egg. 3. The newly hatched salmon, or alevin, encumbered with its legacy of yolk (Y.S.). 4 and 5. The larval salmon, still being nourished from the yolk-sac (Y.S.), which is diminishing in size as the fish grows larger. 6. The salmon fry about six weeks old, with the yolk fully absorbed, so that the young fish has now to feed for itself. The fry become parr, which go to the sea as smolts, and return as grilse. In all cases the small figures to the right indicate the natural size.] [Illustration: THE SALMON LEAPING AT THE FALL IS A MOST FASCINATING SPECTACLE Again and again we see them jumping out of the seething foam beneath the fall, casting themselves into the curtain of the down-rushing water, only to be carried back by it into the depths whence they have risen. One here and another there makes its effort good, touches the upper lip of the cataract, gives a swift stroke of its tail, and rushes on towards those upper reaches which are the immemorial spawning beds of its race.] The Story of the Salmon In late autumn or in winter the salmon spawn in the rivers. The female makes a shallow trough in the gravel by moving her tail from side to side, and therein lays many eggs. The male, who is in attendance, fertilises these with the milt, and then the female covers them deeply with gravel. The process is repeated over and over again for a week or more till all the eggs are shed. For three to four months the eggs develop, and eventually there emerge the larvae or _alevins_, which lurk among the pebbles. They cannot swim much, for they are encumbered by a big legacy of yolk. In a few weeks, perhaps eight, the protruding bag of yolk has disappeared and the _fry_, about an inch long, begin to move about more actively and to fend for themselves. By the end of the year they have grown to be rather trout-like _parr_, about four inches long. In two years these are double that length. Usually in the second year, but it may be earlier or later, the parr become silvery _smolts_, which go out to sea, usually about the month of May. They feed on young herring and the like and grow large and strong. When they are about three and a half years old they come up the rivers as _grilse_ and may spawn. Or they may pass through the whole grilse stage in the sea and come up the rivers with all the characters of the full-grown fish. In many cases the salmon spawn only once, and some (they are called _kelts_ after spawning) are so much exhausted by starting a new generation that they die or fall a victim to otters and other enemies. In the case of the salmon of the North Pacific (in the genus _Oncorhynchus_, not _Salmo_) all the individuals die after spawning, none being able to return to the sea. It must be remembered that full-grown salmon do not as a rule feed in fresh water, though they may be unable to resist