File:EB1911 Mollusca - Development of Paludina vivipara.jpg
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Summary
| Description |
English: Development of the River-Snail, Paludina vivipara. |
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| Date | published 1911 | |||
| Source | “Mollusca,” Encyclopædia Britannica (11th ed.), v. 18, 1911, p. 673, fig. 3. See also “Gastropoda,” v. 11, p. 514, fig. 26. cf. Lankester, Treatise on Zoology, pt. v. (Mollusca), fig. 110, p. 132. | |||
| Author | Edwin Ray Lankester | |||
| Permission (Reusing this file) |
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English: Legend:
| dc, | Directive corpuscle (outcast cell). |
| ae, | Arch-enteron or cavity lined by the enteric cell-layer or endoderm. |
| bl, | Blastopore. |
| vr, | Velum or circlet of ciliated cells. |
| dv, | Velar area or cephalic dome. |
| sm, | Site of the as yet unformed mouth. |
| f, | Foot. |
| mes, | Rudiments of the skeletotrophic tissues. |
| pi, | The pedicle of invagination, the future rectum. |
| shgl, | The primitive shell-sac or shell-gland. |
| m, | Mouth. |
| an, | Anus. |
| A, | Gastrula phase (optical section). |
| B, | The Gastrula has become a Trochosphere by the development of the ciliated ring vr (optical section). |
| C, | Side view of the Trochosphere with commencing formation of the foot. |
| D, | Further advanced Trochosphere (optical section). |
| E, | The Trochosphere passing to the Veliger stage, dorsal view showing the formation of the primitive shell-sac. |
| F, | Side view of the same, showing foot, shell-sac (shgl), velum (vr), mouth and anus. |
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N.B.—In this development the blastopore is not elongated; it persists as the anus. The mouth and stomodaeum form independently of the blastopore. | |
File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 19:00, 19 February 2019 | | 715 × 1,139 (237 KB) | Bob Burkhardt | {{Information |description ={{en|1=Development of the River-Snail, ''Paludina vivipara''.}} |date =published 1911 |source =“Mollusca,” ''Encyclopædia Britannica'' (11th ed.), v. 18, 1911, p. 673, fig. 3. |author =Edwin Ray Lankester |permission ={{PD-Britannica}} }} {{en|Legend:}} {|width="400" |-valign="top" |''dc'',||Directive corpuscle (outcast cell). |-valign="top" |''ae'',||Arch-enteron or cavity lined by the enteric cell-layer or endoderm. |- |''bl'',||Blasto... |
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