File:EB1911 Mollusca - Early division of the Egg-cell in Nassa mutabilis.jpg
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Summary
| Description |
English: Early Stages of division of the Fertilized Egg-cell in Nassa mutabilis (see legend below). |
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| Date | published 1911 | |||
| Source | “Mollusca,” Encyclopædia Britannica (11th ed.), v. 18, 1911, p. 674, fig. 4. | |||
| Author | From Balfour, after Bobretzky. | |||
| Permission (Reusing this file) |
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A, The egg-cell has divided into two spheres, of which the lower contains more food-material, whilst the upper is again incompletely divided into two smaller spheres. Resting on the dividing upper sphere are the eight-shaped “directive corpuscles,” better called “praeseminal outcast cells or apoblasts,” since they are the result of a cell-division which affects the egg-cell before it is impregnated, and are mere refuse, destined to disappear. B, One of the two smaller spheres is reunited to the larger sphere. C, The single small sphere has divided into two, and the reunited mass has divided into two, of which one is oblong and practically double, as in B. D, Each of the four segment-cells gives rise by division to a small pellucid cell. E, The cap of small cells has increased in number by repeated formation of pellucid cells in the same way, and by division of those first formed. The cap will spread over and enclose the four segment-cells. |
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 19:12, 21 February 2019 | | 825 × 632 (249 KB) | Bob Burkhardt | {{Information |description ={{en|1=Early Stages of division of the Fertilized Egg-cell in ''Nassa mutabilis'' (see legend below).}} |date =published 1911 |source =“Mollusca,” ''Encyclopædia Britannica'' (11th ed.), v. 18, 1911, p. 674, fig. 4. |author =From Balfour, after Bobretzky. |permission ={{PD-Britannica}} }} {{en|Legend:}} {| |- | A, The egg-cell has divided into two spheres, of which the lower contains more food-material, whilst the upper is again incomple... |
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