. Commissioners' Game and game-birds; Game protection; Fisheries; Fishes. 436 extracted from the yolk-sac, the latter is absorbed, and the young fish begins to feed for itself. At the end of three months the adult form is attained, the fish being then hardly an inch in length. The length of time which the hatching process takes, and the rapidity with which the developmental process runs vary much in different species of Tebosts, -and is largely dependent on the temperature of the water, spawn deposited in. Fig. 8.—Diagram of several stages in Development of Catflsh. (M->dified from
. Commissioners' Game and game-birds; Game protection; Fisheries; Fishes. 436 extracted from the yolk-sac, the latter is absorbed, and the young fish begins to feed for itself. At the end of three months the adult form is attained, the fish being then hardly an inch in length. The length of time which the hatching process takes, and the rapidity with which the developmental process runs vary much in different species of Tebosts, -and is largely dependent on the temperature of the water, spawn deposited in. Fig. 8.—Diagram of several stages in Development of Catflsh. (M->dified from Ryder). 1, ovarian egg ; 2, egg in which formative j-oke has separated to upper pole ; 3, embryo of second day ; •?, section through such an embryo, showing epiblast with nervous system above, h3'pobla,st below, and] between them the mesoblast and the notochord ; 5 embryo of sixth day. the cold water of October and November not hatcliing till the following spring] in contrast with the rapid process depicted above, which occurs in the early siim-l •mer. The great difference in size which is to be observ^ed between the eg^^i of] different species is not merely proportional to the size of the species, although, asf we shall find, large varieties of brook trout lay larger eg^^s than small varieties ; ibj is largely a question of the relative amnmt of fooJ-yolk provided for the embryo,] -and may be therefore also attiibutcd to the hat<'-lnn_: habit of the specie^, th( longer or shorter time which the embryo takes to burst the egg-shell and to begii to feed for itself. The followinor table jrives the number of egj^s that have been counted tc Si quart in different species :— Mackerel ... 1,207,728 Pickerel (Stlzosiediuon vitreum) 120,000 Whitefish liGUOO Striped Bass 24.,:U)3 Brook Trout 11,000 Lake Trout 8,720 Atlantic Salmon Winninish Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability -
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectfi, booksubjectfishes
