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The primitive mollusc that emerged from our oceans
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Oceanographic Abstracts
foundly decomposed by microbial species inhabiting high latitudes. The liberated biogenic substances are carried by currents into the depths of other geographic areas, thus increasing the reserve of substances taking part in the formation of primary production in these areas of the World Ocean. KRZEMINSKA A., 1961. Granulometric and mineral composition of sands from a so-called Koszalin-Bay cross-section. (In Polish; English summary)Prace Inst. Morsk., Gdansk, (1) Hydrotech., II. Sesja Naukowa Inst. Morsk., 20-21 wrzesnia 1960: 39-52; English summary, 144. (Mimeographed). The analysis of beach and sea-bottom sands aims at determining segregation coefficients for particular zones. It is further attempted to fix definite relations between granulometric qualities and the depth of water, to determine the dislocation and concentration of heavy and light minerals, as well as the presumptive origin of a large part of variable minerals. LAITONE E. V., 1962. Limiting conditions for cnoidal and Stokes waves. J. Geophys. Res., 67 (4): 1555-1564. The second approximation to cnoidal waves is compared with the third approximation for Stokes waves of permanent form in water of finite depth. The comparison clearly indicates that enoidal wave theory should not be applied to finite amplitude waves if their wavelengths are shorter than 5 times the depth. It is shown how the limiting heights of cnoidal waves are also related to the vanishing of the pressure gradient near the wave crest. The third approximation to Stokes waves in finite water depths is verified by the use of the classical small-perturbation expansion method which is best suited for small wave amplitudes. For finite amplitude waves the series expansion in terms of the infinitesimal-wave parameter is found to be most suitable for wave lengths shorter than 8 times the depth. LEMCHE H., 1962. The primitive mollusc that emerged from our oceans. Scientia (Rivista di Scienze), Milano, (6) 97 (1): !1-17. Studies on the primitive mollusc Neopilina galatheae show that molluscs fall into two major systematic groups: Tryblidians and Chitons have traces of metamerism as also found in annelids and arthropods, whereas all other molluscs never evolved much farther than to be tetra-cyclomeric in the manner found in primitive coelenterates, but with one fourth of the body much enlarged--that fourth being the one called by embryologists the D-quadrant. This symmetry is well shown by the dorso-ventral muscles which originally formed an octogon and which appear highly superior to the coelom, etc., as reference structures for determining the relative positions of other organs. This all being true, molluscs may be derived directly from primitive coelenterates and may at the same time be the group from which emerged the annelids and arthropods through multiplication of the originally septal sections. Thereby, the originally ventral subdivisions have gradually expanded to divide also the most aborally placed parts of the body--the neck region and its extension along the dorsum of the D-quadrant. The tentacles of coelenterates may gradually have acquired the structure and function of gills in molluscs, and even at last the arthropod limbs. Originating as it does from several independent sources, the coelom appears of much more doubtful significance for phylogenetical speculation. Probably, our ideas on invertebrate relationships may have to be radically altered if they are to be brought to conform with the evidence at hand in paleontology, embryology, and comparative morphology. LIZITZIN E., 1961. Vedenskorkeusarvoja 1960. Vattenstandsviirden 1960. English summary: Sea level records for the year 1960. Merent. Julk. (Havsf~rskningsinst. Skrift), No. 198:59 pp. This paper contains the results of sea level observations made on the coast of Finland during the year 1960. Observations were made regularly at 13 tide guage (mareograph) and 10 tide pole (pegel) stations. The observation stations arc shown on the map on page 3, the gauge stations being marked by circles and the pole ones by triangles. The numbers refer to column a of Table 1 and Column A of Table 4. The grouping of the observation material is given in the sea level tables. From the tide gauge records, values have been taken for 6 hours daily (2h, 6h, 10h, 14h, 18h, and 22h East-European time, corresponding to Greenwich + 2h), and besides, the monthly and annual means as well as the corresponding extreme values. The monthly and annual extreme values for the tide gauges, given on pages 56-59, have been taken directly from the original registrations. The pole observations are expressed as mean values only. The material has been rearranged according to the principles put forward in the papers Nos. 15, 19, 29, 36, and 43 of the Institute of Marine Research. All the sea level values have been assigned to a reference level lying 200 cm under the mean sea level for the epoch 1921'0. All sea level particulars are given in cm. The monthly extreme values are underlined, interpolated values and even otherwise less exact ones are printed in parentheses. The daily and monthly mean values, in the calculation of which interpolated or otherwise less exact values constitute of 10% or more of all values, are given in parentheses, too.
Oceanographic Abstracts
foundly decomposed by microbial species inhabiting high latitudes. The liberated biogenic substances are carried by currents into the depths of other geographic areas, thus increasing the reserve of substances taking part in the formation of primary production in these areas of the World Ocean. KRZEMINSKA A., 1961. Granulometric and mineral composition of sands from a so-called Koszalin-Bay cross-section. (In Polish; English summary)Prace Inst. Morsk., Gdansk, (1) Hydrotech., II. Sesja Naukowa Inst. Morsk., 20-21 wrzesnia 1960: 39-52; English summary, 144. (Mimeographed). The analysis of beach and sea-bottom sands aims at determining segregation coefficients for particular zones. It is further attempted to fix definite relations between granulometric qualities and the depth of water, to determine the dislocation and concentration of heavy and light minerals, as well as the presumptive origin of a large part of variable minerals. LAITONE E. V., 1962. Limiting conditions for cnoidal and Stokes waves. J. Geophys. Res., 67 (4): 1555-1564. The second approximation to cnoidal waves is compared with the third approximation for Stokes waves of permanent form in water of finite depth. The comparison clearly indicates that enoidal wave theory should not be applied to finite amplitude waves if their wavelengths are shorter than 5 times the depth. It is shown how the limiting heights of cnoidal waves are also related to the vanishing of the pressure gradient near the wave crest. The third approximation to Stokes waves in finite water depths is verified by the use of the classical small-perturbation expansion method which is best suited for small wave amplitudes. For finite amplitude waves the series expansion in terms of the infinitesimal-wave parameter is found to be most suitable for wave lengths shorter than 8 times the depth. LEMCHE H., 1962. The primitive mollusc that emerged from our oceans. Scientia (Rivista di Scienze), Milano, (6) 97 (1): !1-17. Studies on the primitive mollusc Neopilina galatheae show that molluscs fall into two major systematic groups: Tryblidians and Chitons have traces of metamerism as also found in annelids and arthropods, whereas all other molluscs never evolved much farther than to be tetra-cyclomeric in the manner found in primitive coelenterates, but with one fourth of the body much enlarged--that fourth being the one called by embryologists the D-quadrant. This symmetry is well shown by the dorso-ventral muscles which originally formed an octogon and which appear highly superior to the coelom, etc., as reference structures for determining the relative positions of other organs. This all being true, molluscs may be derived directly from primitive coelenterates and may at the same time be the group from which emerged the annelids and arthropods through multiplication of the originally septal sections. Thereby, the originally ventral subdivisions have gradually expanded to divide also the most aborally placed parts of the body--the neck region and its extension along the dorsum of the D-quadrant. The tentacles of coelenterates may gradually have acquired the structure and function of gills in molluscs, and even at last the arthropod limbs. Originating as it does from several independent sources, the coelom appears of much more doubtful significance for phylogenetical speculation. Probably, our ideas on invertebrate relationships may have to be radically altered if they are to be brought to conform with the evidence at hand in paleontology, embryology, and comparative morphology. LIZITZIN E., 1961. Vedenskorkeusarvoja 1960. Vattenstandsviirden 1960. English summary: Sea level records for the year 1960. Merent. Julk. (Havsf~rskningsinst. Skrift), No. 198:59 pp. This paper contains the results of sea level observations made on the coast of Finland during the year 1960. Observations were made regularly at 13 tide guage (mareograph) and 10 tide pole (pegel) stations. The observation stations arc shown on the map on page 3, the gauge stations being marked by circles and the pole ones by triangles. The numbers refer to column a of Table 1 and Column A of Table 4. The grouping of the observation material is given in the sea level tables. From the tide gauge records, values have been taken for 6 hours daily (2h, 6h, 10h, 14h, 18h, and 22h East-European time, corresponding to Greenwich + 2h), and besides, the monthly and annual means as well as the corresponding extreme values. The monthly and annual extreme values for the tide gauges, given on pages 56-59, have been taken directly from the original registrations. The pole observations are expressed as mean values only. The material has been rearranged according to the principles put forward in the papers Nos. 15, 19, 29, 36, and 43 of the Institute of Marine Research. All the sea level values have been assigned to a reference level lying 200 cm under the mean sea level for the epoch 1921'0. All sea level particulars are given in cm. The monthly extreme values are underlined, interpolated values and even otherwise less exact ones are printed in parentheses. The daily and monthly mean values, in the calculation of which interpolated or otherwise less exact values constitute of 10% or more of all values, are given in parentheses, too.