. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine . w Pig. 73. Figs. 73-?5.—A series of diagrams intended to facilitate the comprehension of therelations of the membranes to other parts (after Foster and Balfour). A, B, C, D,E, F are vertical sections in the long axis of the embryo at different periods show-ing the stages of development of the amnion and of the yelk-sac. I, II, III, IVare transverse sections at about the same stages of development, i, ii, iii, pos-terior part of longitudinal section, to illustrate three stages in format
. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine . w Pig. 73. Figs. 73-?5.—A series of diagrams intended to facilitate the comprehension of therelations of the membranes to other parts (after Foster and Balfour). A, B, C, D,E, F are vertical sections in the long axis of the embryo at different periods show-ing the stages of development of the amnion and of the yelk-sac. I, II, III, IVare transverse sections at about the same stages of development, i, ii, iii, pos-terior part of longitudinal section, to illustrate three stages in formation of theallantois. e, embryo; y, yelk; pp, pleuroperitoneal cavity; vt, vitelline mem-brane of amniotic fold;«/, allantois; a, amnion; a, alimentary canal. be expected, the older the embryo the smaller the yelk, or, as itis now called when limited by the embryonic membranes, the REPRODUCTION, 75 \\ m n. 76 COMPARATIVE PHYSIOLOGY. yelk-sac {umbilical vesicle of the mammalian embryo). Themanner in which this takes place will appear npon an inspec-tion of the accompanying figures. Very early in the history of the embryo two eminences, thehead and the tail folds, arise, and, curving over toward each MO.
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1890
