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| Registros recuperados: 51 | |
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| Spoel, S. van der. |
| The columellar muscle system consists anteriorly of a high number of longitudinal branches surrounding a hydrocoel, which forms higher up two lateral, one ventral and four smaller dorsal bundles. These bundles enter the muscular envelope of head and nuchal region, which is formed out of the wing-wall muscles. The two lateral bundles proceed farest apically to insert on the buccal appendages; the four dorsal fibres fuse with the walls of buccal organs and oesophagus, while the ventral muscles run into the posterior and lateral footlobes. The wings are attached to the body by an extra right and left muscle neither derived from the columellar nor from the wing-wall muscle system. So the posterior and lateral footparts are mesopodal, the wings epipodal and the... |
| Tipo: Article / Letter to the editor |
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| Ano: 1982 |
URL: http://www.repository.naturalis.nl/record/505289 |
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| Spoel, S. van der. |
| The vertical distribution patterns of Paraphyllina ransoni Russell, 1956, Periphylla periphylla (Péron & Lesueur, 1809), Atolla parva Russell, 1958, A. vanhoeffeni Russell, 1957, and A. wyvillei Haeckel, 1880 are described. A comparison with other bathypelagic taxa shows that there are various upper limits to be drawn for the bathypelagic area. Four typically different vertical distribution patterns are described. |
| Tipo: Article / Letter to the editor |
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| Ano: 1987 |
URL: http://www.repository.naturalis.nl/record/504330 |
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| Bleeker, J.; Spoel, S. van der. |
| The polychaetous worms collected by the Siboga-Expedition (1899-1900) are listed with some annotations. A few specimens – identified by Augener and Pettibone but never published – are added, so that this list gives a complete survey of all Polychaeta collected by the mentioned expedition. The types of 269 nominal species present in the Institute of Taxonomic Zoology (Zoological Museum), Amsterdam are incorporated in this list, for some species lectotypes are desinated. |
| Tipo: Article / Letter to the editor |
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| Ano: 1992 |
URL: http://www.repository.naturalis.nl/record/505308 |
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| Spoel, S. van der. |
| Part of the “Thor” collections are studied, with the aid of notes by Dr. J.J. Tesch. A new species, Pneumodermopsis (Pn.) teschi, is described, and the variability of some taxonomic characters in Thliptodon are mentioned. A distributional map for the “Thor” records, based on material from the collection of the Zoological Museum in Copenhagen and on the notes left by Tesch, is provided. |
| Tipo: Article / Letter to the editor |
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| Ano: 1973 |
URL: http://www.repository.naturalis.nl/record/505400 |
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| Leyen, A. van; Spoel, S. van der. |
| Re-examination of the Diacria quadridentata species group based upon morphology of the shell and zoogeographic data, led to a new classification comprising the recent taxa: D. quadridentata, D. costata with an equatorial and a central water form, D. danae with an equatorial and a central water form, D. schmidti schmidti, D. erythra crassa and the fossil taxa D. schmidti cocidentalis and D. erythra erythra from surface sediments. A method has been developed to estimate the relative age of the population, based on the development of shell and soft parts. Shell growth in the period of minute and adult stages together does not exceed 0.2 mm, and differs from species to species. |
| Tipo: Article / Letter to the editor |
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| Ano: 1982 |
URL: http://www.repository.naturalis.nl/record/505420 |
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| Spoel, S. van der. |
| The technical details and hydrographie data of the hauls with open nets and opening-closing nets made during the Amsterdam Mid North Atlantic Plankton Expeditions (AMNAPE) in 1982 and 1983 are given together with the general conditions during the sampling periods: 1-27 February 1982 and 27 May – 24 June 1983. Temperature and salinity profiles and correlations are given for the sampled area roughly between 55°N 30°W and 24°N 30°W. |
| Tipo: Article / Letter to the editor |
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| Ano: 1985 |
URL: http://www.repository.naturalis.nl/record/505539 |
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| Spoel, S. van der. |
| The occurrence of aberrant stages in the protandric hermaphrodite Clio pyramidata is considered in relation to the sexual cycle of this species. The anatomy of the juveniles, males and females is shortly discussed especially with regard to their sexual organs. The anatomy of the developing (the normal-complete) and of the growingaberrant stage is briefly reviewed. It is shown that the aberrant stage is formed by strobilation of a normal specimen, probably as a result of less favourable environmental conditions. As the most important conclusions it can be stated that: 1) the aberrant stage described by van der Spoel (1962) is a normal stage in the life cycle; 2) the aberrants are most abundant in the population in the months before the reproductive peaks;... |
| Tipo: Article / Letter to the editor |
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| Ano: 1973 |
URL: http://www.repository.naturalis.nl/record/504282 |
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| Bleeker, J.; Spoel, S. van der. |
| The medusa fauna of the mid North Atlantic Ocean between 24° and 55° N along approximately 30° W is studied. Two Hydromedusae new to science, Oceania tydemani and Annatiara lempersi, are described. The differences in fauna south and north of 42° N, and faunal borders near 50°, 48°, 45°, 35°, 30°, and 34°-37° N are discussed. The vertical distribution and for some species the diurnal migration and subtropical submergence are recorded. |
| Tipo: Article / Letter to the editor |
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| Ano: 1988 |
URL: http://www.repository.naturalis.nl/record/504150 |
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| Spoel, S. van der. |
| INTRODUCTION Specimens of Heteropoda, especially of Atlantidae, which are damaged by the nets and have lost their shells by the action of preservatives are usually considered to be hardly identifiable. Tokioka (1961) used the opercula as a new source of morphological information for the study of the shell-less Atlantidae. The laborious preparation of opercula enables only the identification of some species. The occurrence of groups of closely related taxa showing only slight morphological differences is responsible for other difficulties in identification. Recent expeditions, like the Cicar Expedition, the Eastropac Expeditions and the Acre project provided samples with large quantities of damaged heteropods, which induced me to look for a simple method to... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 42.73. |
| Ano: 1972 |
URL: http://www.repository.naturalis.nl/record/319387 |
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| Spoel, S. van der. |
| The technical details and hydrographical data of the hauls with open nets and opening-and-closing nets, made during the Amsterdam Mid North Atlantic Plankton Expedition are given together with the general conditions during the sampling period April 11 – May 2, 1980. A temperature and salinity profile between 55° and 25°N to a depth of 2000 m are presented with ten XBT records. |
| Tipo: Article / Letter to the editor |
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| Ano: 1981 |
URL: http://www.repository.naturalis.nl/record/505292 |
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| Spoel, S. van der; Pierrot-Bults, A.C.. |
| Cavolinia inflexa (Lesueur, 1813) proves not to be composed of subspecies or formae, or to show clinal variation. Maximum shell length varies between 4 and 7 mm, shell width between 2 and 4 mm, length/width ratio between 0.51 and 0.81. A geographic pattern in the occurrence of different length/width ratios, on which the subdivision of this species was always based in literature, could not be found. Frequency analyses of length for all samples combined did not show subdivision in local populations and length/width ratios over all samples did show only a pattern of shell growth. There is no valid ground for the subdivision of the species into different taxa. |
| Tipo: Article / Letter to the editor |
Palavras-chave: Variation; Taxonomy; Distribution; Cavolinia; Pteropoda.; 42.73. |
| Ano: 1998 |
URL: http://www.repository.naturalis.nl/record/317673 |
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| Registros recuperados: 51 | |
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