Page:Popular Science Monthly Volume 60.djvu/514

506 are always in a well nourished condition. The intestines are surrounded by masses of fat; the muscles in all parts of the body are full and firm, and exhibit innumerable globules of oil within and between the fibers. The sexes are practically indistinguishable. The genitalia amount to only three-tenths of one per cent, of the weight of the animals. During the months from May to December a gradual but steady change takes place. The jaws of the males develop a beak three to five centimeters in length. The skin of both sexes changes color, losing much of its lustar, and becomes loose. The fat about the intestines disappears first; then that contained in the muscles. Certain muscles of the back, which are less important in swimming, diminish to nearly half their original size; and their content of solids to an even greater extent. The muscles most important in swimming, however, are maintained in full vigor; and even in those drawn upon, it is significant that no loss of structure occurs; for on the salmon's return to the sea, this material can be replaced without a reconstruction of the tissue. Just before spawning, the average weight of both sexes is ten per cent, less than that of fish of equal length (eliminating the difference due to the growth of the jaws of the male) caught in May. In contrast with these changes is the growth of the genitalia. The testes or spermaries of the 'ripe' males amount to as much as six per cent, of their body weight, and the ovaries or roe of the females to twenty or even twenty-five per cent., and contain thirty per cent, or more of the total solids of the fish.

While the available information on the subject is as yet by no means so complete as is desirable, on the whole it indicates that the habits of the salmon in other parts of the world, and of other species, are at least similar to those of the Rhine. It is the belief of many of the guides in Maine and New Brunswick that the salmon in their streams do not feed after leaving salt water, and that the 'fly' used to catch them must appeal to their curiosity rather than to their appetite. The salmon in the rivers of Scotland certainly resemble