ALBERT

Description: A systematic study has been made of the Paguridea (exclusive of the Lithodidae) from northwestern North America. In addition to the redescriptions of all known species, two subgenera are herein raised to generic rank and a new genus is described. Several systematic problems have been resolved, and have resulted in the suppression of several specific names familar to North American carcinologists.

Description: The migration of G. zaddachi in La Slack, a small stream on the French Channel coast, and some physico-chemical properties of the river are discussed.\nIn laboratory experiments, the influence of the Cl- and Ca++ concentration on the survival-rate and reproduction of G. zaddachi was investigated. A raise in the Cl- concentration of the medium caused a significant improvement of the survivalrate. A raise in the Ca++ concentration also gives, although not significant, a higher survival-rate.

Description: Dr. Ernst Frederik Jacobi, who was a member of the Editorial Board of this journal for exactly 20 years, reached the age of 65 on September 11, 1973 and retired.\nDr. Jacobi was appointed Director of the Amsterdam Zoo (officially: of the Royal Zoological Society \xe2\x80\x9cNatura Artis Magistra\xe2\x80\x9d) on April 1, 1953, in succession to Dr. A. L. J. Sunier. The function of Director of the Zoo automatically means also the membership of the Editorial Board of \xe2\x80\x9cBijdragen tot de Dierkunde\xe2\x80\x9d. This periodical was published by the Royal Zoological Society until vol. 28 of 1949 (the last volume edited by Dr. Jacobi\xe2\x80\x99s predecessor), but owing to the difficult financial situation of the Society, its publication was interrupted from 1949 to 1959, when vol. 29 appeared. From this volume onward, the \xe2\x80\x9cBijdragen\xe2\x80\x9d appeared at regular periods, first once a year, later twice a year; also, the periodical was no longer published by the Royal Zoological Society solely, but by a committee (called so beautifully the \xe2\x80\x9cBoard of Supervisors on the Management of the Artis Library\xe2\x80\x9d, the Artis Library being the library of the Society, though since 1938 chiefly managed by the University of Amsterdam).

Description: A biography of H. E. van Rijgersma is given, with the genealogical register of his family. The zoological and historical literature, in which he was mentioned, is discussed. Van Rijgersma\'s illustrated manuscripts on botany (1868) and malacology (1875) of St. Martin, and his correspondence with malacologists, were discovered in the United States and studied. The recent mollusk fauna of St. Martin is summarized, consisting of 550 species, of which 136 are new to the fauna of that island.

Description: 1. The migration of two sympatric estuarine species has been studied over a period of one year in the estuary of the river Dourduff, a small river draining into the Bay of Morlaix (Brittany, France). One species, Gammarus zaddachi, is a boreal species and the other, Gammarus chevreuxi, is a lusitanian species. Both species live near the limits of their distribution area. 2. Both species show a migration pattern with an anadromous and a catadromous phase. The migration is an active process. The animals use the tidal movements for their upstream and downstream migration. 3. Migration activities of both species show a diurnal rhythm, the activity peak occurring at night. 4. Downriver migration of both species can be observed throughout the whole year. Upstream migration, however, only takes place during periods with high water spring tide. During these periods the stream reverses direction and water with higher salinities enters the limnic parts of the river. 5. Per night the maximum numbers of anadromous and catadromous migrating individuals caught in a net of 30 X 50 cm were 30,000 and 800,000 respectively for G. chevreuxi. For G. zaddachi these numbers are considerably lower. 6. In both species the composition of the samples from upstream and downstream catches were different. In general, upstream migrating animals are smaller and younger than downstream migrating individuals. 7. G. zaddachi invades the limnic reaches of the river only when water temperatures drop below 6\xe2\x80\x948\xc2\xb0 C, a situation occurring for a period of only a few weeks. 8. G. zaddachi reproduces only during the winter months when water temperatures are relatively low. Reproduction takes place in areas with constant or at least periodical influence of mixohaline waters. In the limnic reaches of the Dourduff reproduction is never observed. 9. G. chevreuxi migrates farther upstream than G. zaddachi. It can stay in completely fresh water for more than four months. 10. G. chevreuxi can reproduce during the whole year. Reproduction has never been observed in completely fresh areas, although downstream migrating ovigerous females can be found. 11. In a series of laboratory experiments, survival rates and reproduction capacity were determined under various different temperature/salinity conditions. 12. Temperature has a strong influence on the salinity tolerance of G. zaddachi. At 5\xc2\xb0 C the mortality rate in river water is comparable to that under optimal salinity conditions. At higher temperatures the mortality sharply increases at lower salinities. 13. Increasing salinity as well as decreasing temperatures have a positive influence upon the reproduction rate of G. zaddachi. In rearing experiments no reproduction has been observed in limnic (= natural) water of the Dourduff, at 5\xc2\xb0 C. 14. For G. chevreuxi the situation is different. At 5\xc2\xb0 C survival is low at all salinities. Under brackish conditions (0.8\xe2\x80\xb0 and 8.0\xe2\x80\xb0 Cl) a rise in temperature results in a higher survival rate. In fresh water however (0.08\xe2\x80\xb0 Cl), rise of temperature causes a higher mortality rate. 15. In rearing experiments G. chevreuxi does not reproduce in completely fresh water. Under mixohaline conditions reproduction has been observed at all temperatures examined. 16. The reproduction cycle of the two species is shown in diagrammatic models.

Description: CONTENTS\nIntroduction................... 4\nPolyorthini Obraztsov................ 6\nKey to the genera of Polyorthini............. 10\nPolyortha Dognin................. 11\nNotes on species of Polyortha Dognin in the collection of the British Museum (Natural History)................ 13\nLophoprora Meyrick................ 18\nL. cyanostacta Meyrick \xe2\x99\x82 \xe2\x99\x80............. 19\nLopharcha Diakonoff................ 21\nSpecies group 1................. 23\nL. quinquestriata Diakonoff \xe2\x99\x82\xe2\x99\x80........... 23\nL. chalcophanes (Meyrick) \xe2\x99\x80............ 25\nL. chionea spec. nov. \xe2\x99\x80.............. 30\nL. halidora (Meyrick) \xe2\x99\x82\xe2\x99\x80............. 31\nL. deliqua spec. nov. \xe2\x99\x80.............. 33\nL. herbaecolor (Diakonoff) \xe2\x99\x82\xe2\x99\x80............ 36\nL. angustior (Diakonoff) \xe2\x99\x80............. 38\nL. rapax (Meyrick) \xe2\x99\x82\xe2\x99\x80.............. 38\nL. orthioterma (Diakonoff) \xe2\x99\x80............ 40\nL. erioptila (Meyrick) \xe2\x99\x82 \xe2\x99\x80............. 43\nL. cryptacantha spec. nov. \xe2\x99\x82\xe2\x99\x80............ 45\nL. maurognoma spec. nov. \xe2\x99\x82............. 49\nL. siderota (Meyrick) \xe2\x99\x80.............. 50\nSpecies group 2................. 50

Description: Two new species and a new subspecies of the Astartidae (Mollusca, Bivalvia) are described from reworked shell material of beaches and estuaries in the Province of Zeeland, The Netherlands. Nomenclatural notes concerning some other species of the same family are added. Furthermore an attempt is made to demonstrate the phylogenetical development of the Astarte (Isocrassina) fusca and the A. (I.) omalii group from the younger Caenozoic (Miocene to Quaternary) of the North Sea Basin.

Description: The Lower Pleistocene succession, the pollen and some smaller mammals from the upper part of the boring Brielle (SW Netherlands) are described. The correlation between the Eburonian Glacial Stage and the mammal-based subdivision of the Biharian Stage is discussed.

Description: A new instrumental method for spectrographical detection of particularities of crystal fields around optically active ions, such as the trivalent chromium ion, was applied to an investigation of red magnesium-spinels from the Ratnapura gem gravels; also from Kangaiyam in India and some other sources for comparison. The method is characterized by analysis of luminescence spectra in the red and near infrared ranges excited by a concentrated flux of blue radiation, and analysed with a spectrograph of considerable optical power. Spectrograms are enregistered on photographic material of high resolving power; they reveal multiplet structures and intensity-distributions of component lines. Slight variations in spectral structure are significant for the detection of structural varieties of minerals. Systematic investigation of the spinels revealed the existence of a hitherto unknown variety of red gem spinel, provisionally named spinelo\xc3\xafd. Its properties are described. Numerical data on the resolved luminescence spectra, in the wavelength range between 6500 \xc3\x85 and 7600 \xc3\x85, are given for the normal and extraordinary varieties. Other physical properties of both varieties are reviewed and compared. The results of the investigation are discussed, and evaluation of data leads to a tentative conclusion regarding the nature of the spinelo\xc3\xafd structure. The spinelo\xc3\xafd is a stoechiometric or near stoechiometric spinel (MgO.Al2O3) in which Cr3+ ions appear in pairs in regular polyhedral configurations; the spectrum is modified by the presence of manganese ions of different valencies.

Description: Both rhodolite and almandine garnets occur in Umba. The rhodolites have no special properties by which they can be distinguished from other garnets in the pyrope-almandine series, except their rose-red colour. Hence a distinctive name is unnecessary. Rutile appears to be the most frequent mineral inclusion in rhodolite, whereas in almandine both apatite and rutile are common. Corundums of different colours occur. Green corundums owe their colour to iron, while blue corundums have a high Ti and a low Cr content. Common inclusions are rutile, pyrrhotite and apatite, whereas graphite especially is found in deep violet corundums. The inclusions in both the garnets and the corundums are not characteristic of this locality. The properties of emerald green and orange-brown tourmalines are given, as well as those of brownish orthopyroxenes, a light green clinopyroxene, yellow scapolite, reddish brown zircon and turquoise.