. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. GENERAL BIOLOGY 729 Propagation During autumn and the last months of the year thermal conditions alter greatly in boreal waters, high temperatures retreating from the surface down to 200 or 300 metres (see Fig. 509). At the same time the sexual organs develop in most boreal food fishes : the cod family, the herrings, the flat-fishes J and others, and during the three or four first months of the y
. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. GENERAL BIOLOGY 729 Propagation During autumn and the last months of the year thermal conditions alter greatly in boreal waters, high temperatures retreating from the surface down to 200 or 300 metres (see Fig. 509). At the same time the sexual organs develop in most boreal food fishes : the cod family, the herrings, the flat-fishes J and others, and during the three or four first months of the year they spawn. Most of these edible fishes possess large ovaries containing enormous numbers of eggs, the cod, for instance, having apparently on the aver- age no less than five million eggs. Late in the 'sixties of Develop- last century, G. O. Sars ZTcT* commenced his investi- gations on the famous cod fisheries in the Lofoten Islands. He found that the eggs of the cod were pelagic, floating in the surface layers of the sea, and he carefully studied the development of these eggs, making a number of excellent drawings, which I regret to say have never been pub- lished. These original drawings foreshadow much of the knowledge gained in recent years on the early development of the cod, and I consider it interesting to reproduce some of them illustrating certain stages. The characters distinguishing these stages are just as law-bound as those of the adult individuals. One stage (see Fig. 520) is characterised by dark transverse bars of black pigment, which subsequently dissolve into fine longi- tudinal bands, following the dorsal and ventral side of the body, a fine stripe running along the lateral line. Later on the. G. O. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Murray, John, Sir, 1841-1914; Hj
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1912
