ALBERT

Description: Among the grasses, preserved at the Rijksherbarium, one of the most valuable collections is certainly that of the well-known agrostologist and collector, B. BALANSA. It contains not only the types of the grasses, described by himself, but also very beautiful material, received by him from his contemporaries. All his European and Oriental grasses, those collected by him in New Caledonia, Tonkin and Java, besides a rich material from his travels in Paraguay and Argentina, are represented in this collection together with a beautiful set of ARECHAVALETA\xe2\x80\x99s grasses form Uruguay. The material is in extraordinarily good condition and was very completely collected by him. I could already describe many novelties from this collection. One of these is particularly interesting on account of questions of geographical distribution.\nVarious botanists have called attention to the fact that there is a rather striking concurrence in the floras of Argentina and some of the southern States of North America and it was STANDLEY who pointed this out, giving a list of analogous species from both countries. It is true that in some cases grasses of the southern States of North America occur in Argentina too. I have already had the opportunity to emphasize this, but generally speaking the coincidence of grasses of both parts of the earth mentioned here, is not so very large if we study the plants more intensively. What I mean is this: in many cases and at first sight, or studying the principal features, a resemblance is very striking, especially also as to the habit and the more prominent characters. But on comparing such plants from North America with the corresponding plants from Argentina, it appears in most of the cases that the two species are not identical. Argentina species of the so very difficult genus of Setaria certainly closely resemble some species from Mexico or the southern Unites States, but in my opinion, they do not belong to the same species. It was especially the genus Aristida which, after an exhaustive study, gave me a better idea of these so-called \xe2\x80\x9dsuccedaneous\xe2\x80\x9c species. As, however, such Argentina species of Aristida differed in a great many minor points from the North American representatives of this group, it was impossible to consider them as really identical and I was so convinced of their specific distinction that I did not hesitate to accept them as new species. It is not difficult to find in other genera of grasses similar convergencies which, in reality, do not exist. Resemblance is only relating to the general habit and the external or easily visible characters, but a great many minor, but very constant and not less striking characters are to be found, through which we are justified to consider them as different species.

Description: ROXBURGH described in his Flora in the year 1820 a very curious annual grass and placed it in the genus Eleusine as E. verticillata ROXB.. This grass has spikelets which agree in many characters with those of the genus Eleusine, especially as to the rugose grain with a caducous pericarp, but differing from Eleusine in the up to 20-flowered spikelets and in the lemmas with a three-cuspidate summit. The many-flowered spikelets give the plant more the habit of an Eragrostis and under this genus a specimen was mentioned by WALLICH in his Catalogue. There are in the characters of the spikelets many other differences with the genus Eleusine and with Eragrostis. KUNTH and STEUDEL, indeed placed the plant under Leptochloa and there are still other opinions about this plant.\nAn advancement in this matter was the opinion of LINDLEY, who published in the year 1836 a new genus Acrachne WIGHT et ARN., in the second edition of his \xe2\x80\x9dNatural System of Botany\xe2\x80\x9c, p. 381, based upon ROXBURGH\xe2\x80\x99s Eleusine verticillata, The name Acrachne was already given by WIGHT et ARNOTT as Acrachne eleusinoides, a nomen in WIGHT, Cat. no. 1760. This name was placed by STEUDEL in the year 1854 under E. verticillata ROXB., a name also accepted by NEES. The name Acrachne, although based upon a species which was validly published, was, however, not described by LINDLEY and the combination A. verticillata was not made by LINDLEY. At that time the genus Acrachne was therefore not valid.

Description: This publication is based on herbarium, materials which were kindly placed at the author\xe2\x80\x99s disposal by the Directors of the Herbarium of the Buitenzorg Botanic Garden (B), the Leiden National Herbarium (L), the Herbarium of the Utrecht University (U), and the Herbarium of the Berlin-Dahlem Botanical Museum (BD), for whose kind help the author wishes to render his best thanks.

Description: During my stay in Spain a rock was found in the surroundings of Ronda, wherein Cycloclypeus was met with by the side of other foraminifera. The scarcity of our knowledge about the occurrence of this genus in Europe and in the Mediterranean Basin, induced me to collect in different parts of Spain, more material wherein Cycloclypeus might occur, especially Oligocene and Miocene rocks. The inducement became even stronger, when a publication by Tan Sin Hok about the genus Cycloclypeus Carpenter, demonstrated the value this genus has for stratigraphy.\nThe results obtained during the examination of the samples, induced me to deviate from my original intention, of giving a survey of the development of the foraminifera-containing Oligocene in some parts of Spain and to try and follow the way indicated by the provisional results. To do so it proved to be desirable to involve other material in this examination.

Description: In het voorjaar van 1937 werd mij vanwege het Rijksmuseum van Geologie en Mineralogie te Leiden voorgesteld in aansluiting aan mijn, toen reeds be\xc3\xabindigd, geologisch onderzoek ten Oosten van de Serio, ook het gebied terzelfder hoogte ten Westen van de Serio, te gaan bewerken.\nTen einde de hieraan verbonden onkosten voor reis en verblijf en een gedeelte der publieatiekosten te kunnen bestreden, deed ik een beroep op de Stichting \xe2\x80\x9eMolengraaff-fonds\xe2\x80\x9d te Delft. Dit beroep is niet tevergeefsch geweest.

Description: Dr. Kuiper and Dr. Nieuwenkamp collected remarkable, etched pieces of dark glass, strongly resembling tektites, in Patagonia. Dr. Ph. H. Kuenen director of the geological institute of the Rijksuniversiteit at Groningen kindly put them at our disposal for investigation. They are now in the Rijksmuseum van Geologie en Mineralogie of Leiden. The chemical analysis and the optical examination showed that these objects are not tektites, but pebbles of volcanic glass.\nFrom Palembang pebbles of obsidian are known, which might be taken for tektites by a layman in these matters, but not by an expert. These pebbles were collected by Prof. Dr. B. G. Escher in 1917 in South-Palembang, Boorterrein Soengei Taham near Moeara Enim, on account of their interesting sculpture. They were analysed together with the well-known obsidian from Goenoeng Kiamis near Garoet (collected by Escher in 1929) and were found to bear much resemblance in chemical respect.

Description: In de zomers van de jaren 1935 en 1936 werd door mij een gebied, gelegen aan de linkerzijde van de Serio, geologisch bewerkt. Dit gebied omvat de meest westelijke toppen en kammen van de Presolanaberggroep. Het behoort vrijwel geheel tot het stroomgebied van de Serio. Terzelfder tijd werkte W.A. Visser in het oostelijk aangrenzend terrein. De resultaten van zijn onderzoek heeft hij alreeds gepubliceerd. J. Weeda bewerkte reeds vroeger het Boven-Serio-dal en het is op zijn verzoek geweest, dat ik mijn onderzoekingen in noordelijke richting heb uitgebreid tot in het Valle Sedornia. Om deze reden bedekken onze kaarten gedeeltelijk elkaar.\nOfschoon vanuit de talrijke grootere dorpen, gelegen in het Valle Seriana en in het Valeggia, een groot deel van het onderzochte terrein kon worden bewerkt, moest toch vele weken gekampeerd worden om ook het oostelijk deel te kunnen onderzoeken. Degenen, die enkele van deze kampementen met mij hebben medegemaakt, dank ik nogmaals voor de vele prettige uren met hen aan het kampvuur doorgebracht.

Description: The investigation of geological structures due to folding led de Sitter to form an opinion on the mechanical problems involved (Bibl. 7). His principal contention is that in simple cases the relative movements of particles with respect to eachother during deformation leading to a fold, have been purely concentric. During such concentric deformation all layers maintain their original thickness and length over the whole profile. All differential movements of neighbouring particles are parallel and therefore concentric. Towards the core of the anticlines and deeper down in the crust the geometrical relations, as construction will show, necessitate a deviation from this principle and either thrusting or plastic thickening of the rocks must take place. The concentric habit for larger units will therefore be partly lost. The most satisfactory treatment of this problem would be a mathematical analysis of the principal normal stresses in a fold, applied to measured properties of the rocks involved. We are still far removed from this ideal solution. De Sitter therefore requested Kuenen to co-operate in an experimental investigation that was intended to elucidate some of the mechanical features of folding and to test the convictions won from the study of folds in nature. The actual experiments were carried out by Kuenen in his laboratory at Groningen. By frequent intercourse, however, de Sitter took an active part in guiding the research. This report embodies the more relevant results. Theoretical considerations have been reduced to a minimum in order to give, as far as possible, an unbiased exposition of the experimental data.\nBefore entering on a description of the experiments some terms and conceptions that will find frequent use must first be discussed. By stress and strain are meant respectively: force per unit surface and deformation in terms of relative displacement.

Description: In 1935 Dr. Ch. Harloff presented a number of metamorphic rocks from Loh-Oelo to the Rijksmuseum van Geologie en Mineralogie of Leyden.\nOne of the most remarkable rocks is a boulder that Harloff discovered in the bed of the Kali Trenggoeloen. The exceptional mineralogical composition rendered a chemical analysis of this rock of importance.

Description: In the first three months of 1937 some Gastrotricha and Kinorhyncha were collected by the author at the beach of Scheveningen. Up to the present no members of these classes were recorded from this part of the North Sea, and moreover, they are all new for the fauna of the Netherlands. Therefore I summarized the results of the examination in the present paper.\nDuring neap tide some sand of the beach was put into glassjars, which were beforehand partially filled with sea water. The sand was taken from the surface of the beach, as near to the water line as possible. As described by Remane (1936, pp. 234\xe2\x80\x94235) the glassjars were put in a quiet spot without aeration for 1\xe2\x80\x942 weeks. After this time every day a proof was taken with a pipette from the surface of the sand, and examined microscopically in Petri-dishes.\nThe collected specimens are inhabitants from the part of the beach that is wetted and dried up twice a day. Therefore the occurrence of these species is "medio-littoral" (Zaneveld, 1937, p. 477). This only incidentally studied habitat is characterized by extraordinary varying conditions, because the structure of the bottom and especially the size of the sand grains is dependent on the mechanical effect of the water movement, on the wind, and on the sunshine. On account of this we can expect a large number of species, recorded from different habitats. The Gastrotricha dealt with here occur in the following biotopics (Remane, 1936, p. 214).\nShell formation: Macrodasys cephalatus and Dactylopodalia typhle.\nCoarse gravel: Dactylopodalia typhle, Platydasys maximus and Aspidiophorus marinus.