. Chemical embryology. Embryology. SECT. 6] OF THE EMBRYO 895 Figs, 232 and 235, the water-content of the whole system rising, that of the yolk remaining steady and that of the embryo slightly falling (82 to 75 per cent.). The total weight of this egg rises considerably, from 76-9 to 132-8 mgm. and as will be shown later, ash as well as water is absorbed during development. The undeveloped egg of 15-0 14-0 13-0 12-0-. 10-0- 100 Sepia contains 40-4 mgm. of water but the hatched embryo ioo-6 mgm. so that 60 per cent, of the final amount must have been taken in from the sea. The percentage of wat
. Chemical embryology. Embryology. SECT. 6] OF THE EMBRYO 895 Figs, 232 and 235, the water-content of the whole system rising, that of the yolk remaining steady and that of the embryo slightly falling (82 to 75 per cent.). The total weight of this egg rises considerably, from 76-9 to 132-8 mgm. and as will be shown later, ash as well as water is absorbed during development. The undeveloped egg of 15-0 14-0 13-0 12-0-. 10-0- 100 Sepia contains 40-4 mgm. of water but the hatched embryo ioo-6 mgm. so that 60 per cent, of the final amount must have been taken in from the sea. The percentage of water in the system correspondingly rose from 52-5 to 75-81. The work of Weismann indicated a similar absorption of water during the embryogeny of the cladoceran, Daphnia, and this was con- 1 An equation for the egg of the axolotl, Amblystoma, can be derived from Dempster's data : Wet + External = Wet + Dry yolk used for yolk water axolotl other purposes (i-ogm.) (3-92 gm.) (4-84 gm.) (0086 gm.) Ranzi's figures apply to the pre-hatching period only, Dempster's apply to the whole yolk-sac period as 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 Needham, Joseph, 1900-. New York: The MacMillan Co.
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Keywords: ., bookcentury1900, bookpublishernewyorkthem, booksubjectembryology
