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| Slijper, E.J.. |
| Nachdem die fossilen Früchte und Samen aus dem Ton von Reuver, von C. und E. M. Reid, und die Blätter von Laurent und Marty eingehendst studiert worden sind, schien es mir erwünscht auch die Hölzer, die in so grosser Zahl in den Tonschichten Vorkommen einer Untersuchung zu unterwerfen. In der Tongrube der Firma Teeuwen zu Reuver, die ein wenig jenseits der holländischdeutschen Grenze auf deutschem Gebiet am Nordrand des Icksbergs gelegen ist, wurden von mir am 16. September 1930 aus jeder der Schichten des damals blossgelegten Profils eine grosse Anzahl von Holzresten gesammelt. Die Anfertigung der Schnitte für microscopische Untersuchung war nicht schwer, ein gewöhnliches Rasiermesser genügte zu diesem Zweck. Nach einer Behandlung mit kochender Kalilauge... |
| Tipo: Article / Letter to the editor |
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| Ano: 1932 |
URL: http://www.repository.naturalis.nl/record/534965 |
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| Slijper, E.J.. |
| INHALTSÜ BERSICHT Abschnitt 1 Einleitung; Material .... 243 I Strandung .... 243 II Material .... 244 Abschnitt 2 Nomenklatur; Geographische Verbreitung; Lebensweise .... 245 I Nomenklatur .... 245 II Geographische Verbreitung .... 246 III Lebensweise .... 249 Abschnitt 3 Äussere Form; Wachstum .... 250 I Äussere Form .... 250 II Wachstum .... 251 Abschnitt 4 Skelett .... 252 I Wirbelsäule .... 252 II Rippen .... 255 III Sternum .... 255 IV Becken .... 257 V Vorderextremität .... 258 VI Schädel .... 260 VII Zähne .... 260 Abschnitt 5 Muskelsystem .... 262 I Der M. scalenus .... 262 II Die Bauchmuskeln .... 263 A Anatomisches .... 263 1 Allgemeine Lage- und Ursprungsverhaltnisse .... 263 2 Die Rectusscheide .... 265 |
| Tipo: Article / Letter to the editor |
Palavras-chave: 42.84. |
| Ano: 1939 |
URL: http://www.repository.naturalis.nl/record/318156 |
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| Slijper, E.J.. |
| 1. Researches were made on 50 hearts of 9 different Pinnipeds, of the Hippopotamus and the Otter. 2. In the Northern Fur Seal, the Grey Seal, the Ringed Seal, the Bearded Seal, the Banded Seal and the Walrus the ductus arteriosus closes anatomically at the same time, or even earlier, than in terrestrial Mammals of comparable size. In contrast to those of the Common Seal the newborn pups of these animals remain on land for several weeks, or, if they swim during the first weeks after birth, they do so infrequently and they do not dive. These data confirm the supposition that the retarded anatomical closure of the ductus arteriosus in Cetaceans and in the Common Seal may be explained by the fact that their newborns swim and dive immediately or almost... |
| Tipo: Article / Letter to the editor |
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| Ano: 1968 |
URL: http://www.repository.naturalis.nl/record/504597 |
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| Slijper, E.J.. |
| 1. A review is given of some phenomena concerning pregnancy and parturition of the Cetacea, depending on data in literature and on observations made in Antarctic Blue and Fin Whales on board the f.f. “Willem Barendsz” (1946—1947). 2. In Mystacoceti the frequency of twins appears to be less than in man and the big domestic animals. The majority of twins is born by females that are longer than the average female in the period of greatest sexual activity. This does not mean, however, that just as in man most twins are born at an elder age than that corresponding with the maximum of sexual activity. It may also be possible that, just as in the big domestic animals, the ages correspond, but that twins are mostly produced by the physically stronger developed... |
| Tipo: Article / Letter to the editor |
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| Ano: 1949 |
URL: http://www.repository.naturalis.nl/record/503926 |
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| Doorn, C. van; Slijper, E.J.. |
| At the Royal Zoological Gardens “Blijdorp” at Rotterdam May 6th 1958 a Father David’s Deer gave birth to a female calf. It was the first young of this three year old doe. During the days before the day of birth the doe was seen several times leaping upon the buck. Experience with other Ungulates has taught that such behaviour may be regarded as an indication that the time of delivery is approaching. On the day of birth the doe refused her food as has been observed in many other mammals. She lay down very often, gnashed her molar teeth and made movements with her head towards the belly and the udder, the ears flattened to the neck, as if she was suffering from cramps. One had the impression, however, that the expulsion of the young was kept back until the... |
| Tipo: Article / Letter to the editor |
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| Ano: 1959 |
URL: http://www.repository.naturalis.nl/record/503991 |
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| Slijper, E.J.; Utrecht, W.L. van; Naaktgeboren, C.. |
| A. GENERAL REMARKS During three years 4500 reports of whales sighted from Netherlands ships were collected, bearing on approximately 11.000 individual animals. Most of the observations were made in the Atlantic and Indian Ocean. It was supposed that the species could be determined with a fairly high degree of reliability in the case of Humpback Whales, Sperm Whales and Right Whales. No distinction could be made between Blue, Fin, Sei and Bryde Whales. They were collected under the heading Rorquals. Catches of land stations and strandings of whales, however, indicate that in all areas, at least a part of these Rorquals must have been Blue or Fin Whales. Probably the majority of this part were Fin Whales. Nevertheless it must he emphasized that the... |
| Tipo: Article / Letter to the editor |
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| Ano: 1964 |
URL: http://www.repository.naturalis.nl/record/503965 |
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