Third annual catalogue of the Cyphers Incubator Co . tion. The germinal membrane has spread over thewhole of the yolk sac, and the yolk is thus com-pletely enclosed in a bag whose walls, however,are excessively delicate and easily torn. Thevascular area extends over about two-thirds of By the seventh day very obvious movementsbegin to appear in the amnion ; its slow vermicu-lar contractions creep rhythmically over it. Theamnion, in fact, begins to pulsate slowly andrhythmically, and by its pulsation the embryo isrocked to and fro in the egg. Similar move-ments are also seen in the allantois at
Third annual catalogue of the Cyphers Incubator Co . tion. The germinal membrane has spread over thewhole of the yolk sac, and the yolk is thus com-pletely enclosed in a bag whose walls, however,are excessively delicate and easily torn. Thevascular area extends over about two-thirds of By the seventh day very obvious movementsbegin to appear in the amnion ; its slow vermicu-lar contractions creep rhythmically over it. Theamnion, in fact, begins to pulsate slowly andrhythmically, and by its pulsation the embryo isrocked to and fro in the egg. Similar move-ments are also seen in the allantois at a consider-ably later period. The growth of the allantois has been veryrapid, and it forms a flattened bag covering theright side of the embryo, and rapidly spreading 21 THE CYPHERS INCUBATOR COMPANY out in the direction between the primitive foldsof the amnion, that is between the amnion properand the false amnion, or chorion. It is filledwith fluid, so that in spite of its flattened form itsopposite walls are distinctly separated from Fig. 5.—A diagrammatic section through the fowl s egg abouteleven days incubated. Al, cavity of the allautois ; alb, albumen ;am, cavity of the amnion ; um, umbilicus, or smal hollow tube con-necting the embryo with the amnion, yolk-sac and allantois. Theouter covering of the umbilicus is formed by the amnion, and iscontinuous with the body wall of the embryo. Through this tubepasses that of the allantois, and also that of the yolk-sac. By meansof the latter the walls of the alimentary canal are contini:ous withthe membrane covering the yolk-sac, and the interior of the canal iscontinuous with the inside of the yolk-sac. At a comparativelyearly period the canal of this stalk becomes obliterated, so that thematerial of the yolk can no longer pass directly into the alimentarycavity, but has to find its way into the body of the chick by absorp-tion through the blood-vessels. jWhen in the last days of incubation the greatly diminished
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpoultryfeedingandfee
