. Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus. Vertebrates -- Embryology; Comparative embryology. YOLK MATERIAL. VAGE PLANE OLAR BODIES Fig. 132. Movement of ooplasmic substances in the egg of Styela (Cynthia) partita at the time of fertilization. (All figures after Conklin, '05.) (A) Unfertilized egg after the disappearance of the nuclear membrane of the germinal vesicle. The gray yolk is shown in the center of the egg. surrounded by the yellow-pigmented cytoplasm. The test cells and chorion surround the egg. (B) Egg five minutes after fertil
. Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus. Vertebrates -- Embryology; Comparative embryology. YOLK MATERIAL. VAGE PLANE OLAR BODIES Fig. 132. Movement of ooplasmic substances in the egg of Styela (Cynthia) partita at the time of fertilization. (All figures after Conklin, '05.) (A) Unfertilized egg after the disappearance of the nuclear membrane of the germinal vesicle. The gray yolk is shown in the center of the egg. surrounded by the yellow-pigmented cytoplasm. The test cells and chorion surround the egg. (B) Egg five minutes after fertilization, showing the streaming of the peripheral protoplasm indicated by arrows toward the vegetal pole, where the sperm has entered. The gray yolk is shown in the upper part of the egg below the nuclear material. The clear protoplasm, derived from the nuclear sap of the germinal vesicle, also flows down with the peripheral protoplasm. (C) Side view of an egg after peripheral protoplasm has migrated to the vegetal pole of the egg. The clear protoplasm is shown at the upper edge of the yellow cap. The polar bodies are forming in the midpolar area (MP.) at the animal pole. (D) Side view of the egg showing the yellow crescent and the area of clear protoplasm above the yellow crescent. The yolk material is shown at the vegetal pole below and to one side of the yellow crescent. (E) Yellow crescent and clear protoplasm viewed from the posterior pole of the egg. Animal pole is above the crescent; yolk material is below. (F) Same view as (E) a little later, showing the external beginnings of the first cleavage. The polar bodies are shown above the crescent material. (G) View similar to that of (E, F) a little later. The first cleavage is complete. Observe that the clear protoplasm and the yellow crescent have been bisected equally. The cleavage plane corresponds to the median axis of the embryo. 264. Please note that these images are extracted from scanned page images that may have bee
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