Matching and surface barrier effects of the flux-line lattice in superconducting films and multilayers.

The flux-line lattice dissipation and the pinning force of Bi2Sr2CaCu2O8 and YBa2Cu3O7 films and a Nb/Cu multilayer are investigated with the vibrating reed technique. In magnetic fields oriented under a small angle with respect to the film surfaces the Bi-2:2:1:2 film shows a series of pronounced dissipation maxima at matching fields BN in the irreversible region of the magnetic phase diagram. The Y-1:2:3 film shows tiny damping maxima, whereas no structure in the dissipation of the Nb/Cu multilayer is detected below the upper critical field. The comparison of the matching fields to an anisotropic London model shows that the dissipation maxima are caused by rearrangements of the flux-line lattice configuration due to interactions with the sample surface. The different behavior of the high-temperature superconductors and the Nb/Cu multilayer is understood by explicitly taking the surface barrier into account. Deviations from the surface induced commensurability of the flux-line lattice due to the intrinsic pinning are discussed. Our results indicate that pancake vortices in the Bi-2:2:1:2 film should be coupled below the irreversibility line and below magnetic fields B??0.5 T perpendicular to the film surface

Notes upon some Sea Turtles

In recent years much attention is being paid to marine turtles, and it is the merit of Deraniyagala, Carr, and others to have contributed much to our knowledge of this group. Nevertheless, our knowledge of the species and subspecies that may be recognized, and that of their distribution is as yet far from complete. Before a satisfactory classification can be reached, many more data will have to be assembled. In the meantime, notes on variations in individual cases, and locality records may be of some value to future research. It is with this in mind that the present notes are published. They are based upon specimens in the collections of the Rijksmuseum van Natuurlijke Historie, Leiden (ML), of the Zoölogisch Museum, Amsterdam (ZMA), of the British Museum (Natural History), London (BM), and of the Royal Scottish Museum, Edinburgh (RSM). I am greatly indebted to Prof. Dr. H. Engel (Amsterdam), to Dr. H. W. Parker, Miss A. G. C. Grandison and Mr. J. C. Battersby (London), and to Dr. A. S. Clarke (Edinburgh) for permission to study the specimens in their care, and to Dr. E. Williams (Cambridge, Mass.) for information about turtles in the Museum of Comparative Zoölogy. Deraniyagala (1939 a-b; 1943, pp. 79-80; 1952, p. 57) and Wermuth (1956, pp. 405, 406, 413) raised some nomenclatorial problems, and these are also discussed in the present notes. The drawings reproduced in figures 2-8 do not pretend to be anything more than sketches; they were made without the help of instruments, and although they may prove to show slight errors in the proportions of the shields, I believe that they are sufficiently accurate to illustrate the features discussed in the text

Frogs and snakes from the island of Morotai (Moluccas)

Van Kampen (1924, p. 284) mentions only two species of frogs from Morotai Island; the identification of one of these was considered to be doubtful. Of snakes De Jong (1928, p. 149) records five species from this island. The study of a small collection of frogs and snakes from Morotai, presented to the Leiden Museum in 1862 by H. A. Bernstein, and of two frogs collected by Prof. H. J. Lam in 1926, allows of some additions to be made to previous lists. The species not mentioned by either Van Kampen or De Jong are indicated by an asterisk. * Hyla infrafrenata Gthr. 4 specimens, Morotai, leg. H. A. Bernstein, 1862, reg. no. 1833. * Hyla rueppelli Bttgr. 2 ♂ ♂, between Bilowoh and Goegoeti, Morotai, VI. 1926, leg. Prof. H. J. Lam. These two specimens show some differences from Hyla rueppelli, such as this species has been described from Halmaheira by Boettger (1895, p. 137; 1900, p. 373, pl. XVI figs. 12-12c). The tympanum is relatively larger; its diameter equals about half that of the eye. The groups of vomerine teeth are not circular as shown in Boettger's fig. 12c, but they are more oblong. They are placed between the choanae and not at the level of the posterior border of the choanae. In one specimen the vomerine teeth have only very weakly developed. The snout is slightly longer than the diameter of the orbit. The sides of both males show a network of brownish lines surrounding whitish spots; these whitish spots are most distinct on the anterior half of the sides. Both males have a nuptial callosity on the outer surface of the firs

Ueber die Identität von Thecadactylus pollicaris Spix 1825 mit Phyllopezus goyazensis Peters 1877. Von Lorenz Müller (Zoolog. Staatssaammlung, München) und L. D. Brongersma ('s Rijks Museum van Natuurlijke Historie, Leiden)

Der von SPIX im Jahre 1825 in „Species novae Lacertarum" auf Seite 17 beschriebene und auf Tafel 18 Fig. 2 abgebildete Thecadactylus pollicaris wurde von CUVIER „Règne animal II" Seite 54 in die Synonymie von G(ecko) mabuia (= Hemidactylus mabouia MOR.) versetzt und die meisten späteren Autoren schlossen sich dieser Ansicht an. DUMÉRIL und BIBRON führen in Band III ihrer „Erpétologie générale" S. 362 die Spixsche Art allerdings nur mit einem Fragezeichen in der Synonymie von Hemidactylus mabouia auf und auch GRAY „ Catalogue of Lizards" S. 154 folgt ihrem Beispiel. Aber seitdem PETERS, der die Spixschen EidechsenArten einer Revision unterzog (Monatsber. Akad. Berlin 1877), Thecadactylus pollicaris SPIX in die Synonymie von Hemidactylus tuberculosus RADDI (= Hemidactylus mabouia Mor.) versetzt hatte, bestand offenbar kein Zweifel mehr an der Identität der beiden Arten. Nur Schlegel hatte im Jahre 1858 (Handl. Dierk. II, S. 15) Th. pollicaris unter dem Namen Platydactylus pollicaris als eigene Art aufgeführt ohne indes seine Ansicht zu begründen. Daß sie aber berechtigt war, soil in folgendem ausgeführt werden. Bei einer Durcharbeitung der herpetologischen Sammlung des Rijksmuseum van Natuurlijke Historie in Leiden fand der jüngere von uns beiden ein Glas mit einem Gecko, das folgendermaßen etikettiert war: Hemidactylus mabouia Mor. sn. Thecadactylus pollicaris SPIX. SPIX Brésil Dieses Exemplar, daß das Leidener Museum durch SPIX selbst erhielt, stimmt sehr gut mit der von ihm gegebenen Beschreibung und Abbildun

[Rijksmuseum van Geologie en Mineralogie, 1878-1978 = The Rijks Museum for Geology and Mineralogy, 1878-1978 / P.C. Zwaan (editor)]: Rijksmuseum van Geologie en Mineralogie 1878 - 1978 : past, present, and future

The Past 38 Period before 1751 38 1751-1820 39 1820-1878 43 1878-1922 52 1922-1955 57 1955-1961 61 1961-1972 63 The Present (from 1972 onwards) 66 The Future 68 University teaching 70 Other teaching activities 72 The status and position of RGM 72 Acknowledgements 76 Notes 77 References 85 Appendix I 88 Appendix II 91 On the first of November, 1978, the Rijksmuseum van Geologie en Mineralogie (National Museum of Geology and Mineralogy), commemorated the day upon which, one hundred years ago, the first step was set on its way to independence. This gives occasion to review its past, its present state, as well as to try and look into its future. It will be evident that when discussing the present state and the possible future development of the museum (unless stated otherwise) the opinion given is that of the present author

Snakes from the Leeward Group, Venezuela and eastern Colombia

Dr. P. Wagenaar Hummelinck entrusted me with the study of the snakes, which he collected during his trips to the islands off the north coast of Venezuela, to the Venezuelan mainland, and to eastern Colombia. In the present paper the species collected by Dr. Hummelinck are listed with data on scale counts, coloration and with notes on nomenclature. In a few cases specimens from other collections were used for comparison, and for these the provenance is indicated in the lists of specimens. Dr. Hummelinck made notes on the names given to the different species of snakes by the inhabitants, and by his kind permission these notes are included in the present paper. These local names form an addition to those published by Roca (1932, pp. 387—388). Unless otherwise stated the specimens are in the collections of the Rijksmuseum van Natuurlijke Historie, Leiden. The numbers cited for the different specimens, Oph. 1—60, are the numbers used by the collector; they are mentioned in parentheses, the first of each list of specimens with the indication Oph., the following without this indication