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| Bock, J.F. de. |
| The primary differentiation within the genus Miogypsina is based on features seen in vertical sections. The subgenus Miogypsinoides lacks lateral chambers and the equatorial plane is covered on each side by zones of massive laminae, whereas the subgenus Miogypsina has well-developed lateral chambers on each side of the equatorial layer. Miogypsinoides shows an intraseptal canal system, due to the presence of a toothplate and a septal flap which are not found in Miogypsina s.s. Several samples contained specimens which show the possible transition from Miogypsinoides to Miogypsina s.s. The disappearance of the septal flap and the toothplate in Miogypsina was probably simultaneous with the appearance of lateral chambers. It seems that the existence of... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.20. |
| Ano: 1976 |
URL: http://www.repository.naturalis.nl/record/317461 |
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| Bock, J.F. de. |
| In spite of the generally poor preservation of the specimens, it could be observed that in many specimens the large, often somewhat trochoid spiral out of PA-I, surrounding I and II, passes the small spiral out of PA-II without forming a closing chamber. In several specimens the vertical section shows that the embryonic-nepionic apparatus forms an angle with the equatorial plane. This makes it difficult to distinguish in a horizontal thin section a spiral chamber from an equatorial or lateral chamber. The sample used contained numerous microspheric specimens, which are markedly different from the megalospheric specimens both externally and internally. The difference between the subgenera Miogypsina and Miolepidocyclina is discussed. |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.20. |
| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/317497 |
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| Bock, J.F. de. |
| Excellent scanning electron micrographs of embryonal structures of bispiral Miogypsina's were made, which solve a number of problems raised by details seen in thin sections. Special attention has been paid to the stolon-system near the second primary auxiliary chamber (ΡΑ-II). From the deuteroconch to the ΡΑ-II two funnel-shaped stolons cross the cylindrical protoconchal stolon on both sides. Once a 'lip' around the protoconchal stolon was discovered, it turned out to exist in nearly all the bispiral specimens. |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.22. |
| Ano: 1973 |
URL: http://www.repository.naturalis.nl/record/317395 |
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