. The development of the chick; an introduction to embryology . y of the cup is the future posterior chamber of the eye;it has two openings, viz., the pupil filled by the primordium ofthe lens, and the slit-like choroid fissure extending from the pupilto the optic stalk along the ventral surface. The retinal layeris continuous with the floor of the optic-stalk, and thus with thediencephalon. The optic cup expands with extreme rapidity between thestages of 26 and 36 somites, as may be seen from the figures bycomparing the relative size of the lens and optic cup at differentstages. The Lens. The
. The development of the chick; an introduction to embryology . y of the cup is the future posterior chamber of the eye;it has two openings, viz., the pupil filled by the primordium ofthe lens, and the slit-like choroid fissure extending from the pupilto the optic stalk along the ventral surface. The retinal layeris continuous with the floor of the optic-stalk, and thus with thediencephalon. The optic cup expands with extreme rapidity between thestages of 26 and 36 somites, as may be seen from the figures bycomparing the relative size of the lens and optic cup at differentstages. The Lens. The invagination of the thickened ectodermexternal to the optic vesicle soon leads to the formation of a deep,thick-walled pit which rapidly closes (26-28 somites) and thus FROM TWELVE TO THIRTY-SIX SOMITES ]67 forms an epithelial sac, which at first practically fills the cavityof the optic cup. However, it very soon becomes detached fromthe posterior wall of the optic cup, which expands with greatrapidity, and the lens is left at the mouth of the cup. The walls. §■ 5o ;/ 5 ^ ^ v
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Keywords: ., bookauthorlilliefrankrattray187, bookcentury1900, bookdecade1910
