ALBERT

Notes: Andalusite porphyroblasts are totally pseudomorphosed by margarite–paragonite aggregates in aluminous pelites containing the peak mineral assemblage andalusite, chlorite, chloritoid, margarite, paragonite, quartz ± garnet, in a NW Iberia contact area. Equilibria at low P–T are investigated using new KFMASH and (mainly) MnCNKFMASH grids constructed with Thermocalc 3.21. P–T and T–X pseudosections with phase modal volume isopleths are constructed for compositions relatively richer and poorer in andalusite to model the assemblages in an andalusite-bearing rock that contains a thin andalusite-rich band (ARB) during retrogression. Their compositions, prior to retrogression, are used in the modelling, and have been retrieved by restoring the pseudomorph-forming elements into the current-depleted matrix, except for Al2O3 which is assumed to be immobile. Compositional differences between the thin band and the rest of the rock have not resulted in differences in andalusite porphyroblast retrogression. The absence of chloritoid resorbtion implies either a pressure increase at constant reacting-system composition, or that its composition changed during retrogression at constant pressure, by becoming enriched in the progressively replaced andalusite porphyroblasts. T–X pseudosections at 1 kbar model this latter process using as end-members in X, first, the restored original rock and ARB compositions, and, then the same process, taking into account the change in composition of both as retrogression proceeded. The MnNCKFMASH pseudosections of rocks with different Al contents facilitate making further deductions on the rock-composition control of the resulting assemblages upon retrogression. Andalusite eventually disappears in relatively Al-poor rocks, resulting, as in this study, in a rock formed by chloritoid–chlorite as the only FM minerals, plus margarite–paragonite pseudomorphs of andalusite. In rocks richer in Al, chlorite would progressively disappear and a kyanite/andalusite–chloritoid assemblage would eventually be stable at retrograde conditions. The Al-silicate, stable during retrogression in Al-rich rocks, indicates pressure conditions and hence the tectonic context under which retrogression took place.

Notes: In statistically optimised P–T estimation, the contributions to overall uncertainty from different sources are represented by ellipses. One source, for a diffusion-controlled reaction at non-equilibrium, is diffusion modelling of the reaction texture. This modelling is used to estimate ratios, Q, between free-energy differences, ΔG, of reactions among mineral end-members, to replace the equilibrium condition ΔG = 0. The associated uncertainty is compared with those already inherent in the equilibrium case (from end-member data, activity models and mineral compositions). A compact matrix formulation is introduced for activity coefficients, and their partial derivatives governing error propagation. The non-equilibrium example studied is a corona reaction with the assemblage Grt–Opx–Cpx–Pl–Qtz. Two garnet compositions are used, from opposite sides of the corona. In one of them, affected by post-reaction Fe, Mg exchange with pyroxene, the problem of reconstructing the original composition is overcome by direct use of ratios between chemical-potential differences, given by the diffusion modelling. The number of geothermobarometers in the optimisation is limited by near-degeneracies. Their weightings are affected by strong correlations among Q ratios. Uncertainty from diffusion modelling is not large in comparison with other sources. Overall precision is limited mainly by uncertainties in activity models. Hypothetical equilibrium P–T are also estimated for both garnet compositions. By this approach, departure from equilibrium can be measured, with statistical uncertainties. For the example, the result for difference from equilibrium pressure is 1.2 ± 0.7 kbar.

Notes: This paper characterizes the metamorphic thermal structure of the Higo Metamorphic Complex (HMC) and presents the results of a numerical simulation of a geotherm with melt migration and solidification. Reconstruction of the geological and metamorphic structure shows that the HMC initially had a simple thermal structure where metamorphic temperatures and pressures increased towards apparent lower structural levels. Subsequently, this initial thermal structure has been collapsed by E–W and NNE–SSW trending high-angle faults. Pressure and temperature conditions using the analysis of mineral assemblages and thermobarometry define a metamorphic field P–T array that may be divided into two segments: the array at apparent higher structural levels has a low-dP/dT slope, whereas that at apparent lower structural levels has a high-dP/dT slope. This composite array cannot be explained by heat conduction in subsolidus rocks alone. Migmatite is exposed pervasively at apparent lower structural levels, but large syn-metamorphic plutons are absent at the levels exposed in the HMC. Transport and solidification of melt within migmatite is a potential mechanism to generate the composite array. Thermal modelling of a geotherm with melt migration and solidification shows that the composite thermal structure may be formed by a change of the dominant heat transfer from an advective regime to a conduction regime with decreasing depth. The model also predicts that strata beneath the crossing point will consist of high-grade solid metamorphic rocks and solidified melt products, such as migmatite. This prediction is consistent with the observation that migmatite was associated with the very high-dP/dT slope. The melt migration model is able to generate the very high-dP/dT segment due to the high rate of heat transfer by advection.

Notes: Sapphirine, coexisting with quartz, is an indicator mineral for ultrahigh-temperature metamorphism in aluminous rock compositions. Here a new activity-composition model for sapphirine is combined with the internally consistent thermodynamic dataset used by THERMOCALC, for calculations primarily in K2O-FeO-MgO-Al2O3-SiO2-H2O (KFMASH). A discrepancy between published experimentally derived FMAS grids and our calculations is understood with reference to H2O. Published FMAS grids effectively represent constant aH2O sections, thereby limiting their detailed use for the interpretation of mineral reaction textures in compositions with differing H2O.For the calculated KFMASH univariant reaction grid, sapphirine + quartz assemblages occur at P–T in excess of 6–7 kbar and 1005 °C. Sapphirine compositions and composition ranges are consistent with natural examples. However, as many univariant equilibria are typically not ‘seen’ by a specific bulk composition, the univariant reaction grid may reveal little about the detailed topology of multi-variant equilibria, and therefore is of limited use for interpreting the P–T evolution of mineral assemblages and reaction sequences. Calculated pseudosections, which quantify bulk composition and multi-variant equilibria, predict experimentally determined KFMASH mineral assemblages with consistent topology, and also indicate that sapphirine stabilizes at increasingly higher pressure and temperature as XMg increases. Although coexisting sapphirine and quartz can occur in relatively iron-rich rocks if the bulk chemistry is sufficiently aluminous, the P–T window of stability shrinks with decreasing XMg. An array of mineral assemblages and mineral reaction sequences from natural sapphirine + quartz and other rocks from Enderby Land, Antarctica, are reproducible with calculated pseudosections. That consistent phase diagram calculations involving sapphirine can be performed allows for a more thorough assessment of the metamorphic evolution of high-temperature granulite facies terranes than was previously possible. The establishment of a a-x model for sapphirine provides the basis for expansion to larger, more geologically realistic chemical systems (e.g. involving Fe3+).

Notes: Large garnet poikiloblasts hosted by leucosome in metapelitic gneiss from Broken Hill reflect complex mineral–melt relationships. The spatial relationship between the leucosomes and the garnet poikiloblasts implies that the growth of garnet was strongly linked to the production of melt. The apparent difficulty of garnet to nucleate a large number of grains during the prograde breakdown of coexisting biotite and sillimanite led to the spatial focussing of melting reactions around the few garnet nuclei that formed. Continued reaction of biotite and sillimanite required diffusion of elements from where minerals were reacting to sites of garnet growth. This diffusion was driven by chemical potential gradients between garnet-bearing and garnet-absent parts of the rock. As a consequence, melt and peritectic K-feldspar also preferentially formed around the garnet. The diffusion of elements led to the chemical partitioning of the rock within an overall context in which equilibrium may have been approached. Thus, the garnet-bearing leucosomes record in situ melt formation around garnet porphyroblasts rather than centimetre-scale physical melt migration and segregation. The near complete preservation of the high-grade assemblages in the mesosome and leucosome is consistent with substantial melt loss. Interconnected networks between garnet-rich leucosomes provide the most likely pathway for melt migration. Decimetre-scale, coarse-grained, garnet-poor leucosomes may represent areas of melt flux through a large-scale melt transfer network.

Notes: The paper presents a straightforward method of calculating approximate orientation parameters (six degrees of freedom) of a known targeted object relative to a single calibrated camera. These can then initialise an optimised non-linear calculation of the same parameter values. The method uses the mathematics of a scaled parallel projection and is particularly suited to narrow angle images obtained using a telescope, telephoto or zoom lens. However, the method can also be used with cameras having wider fields of view provided the target group occupies a moderately small part of the image.

Notes: This paper describes three mathematical modelling methods for high-resolution declassified CORONA KH-4B images. Since CORONA images are collected with a panoramic camera, several types of geometric distortions are involved. Two methods use the modified collinearity equations, and the third involves the terrain-dependent rational function model (RFM) which is considered to be a generic sensor model. Comparative analysis of the three mathematical modelling methods is undertaken. The results show that a ± 1·5 pixels level of horizontal and vertical accuracy can be obtained. A digital elevation model (DEM) of a test site is also created.

Notes: Digital photogrammetry and softcopy workstations have added a new dimension to aerial triangulation, and some of the previously manual procedures are now available in automated form. Also, commercial software packages for automatic aerial triangulation came on to the market in the last decade. In this study, the results of automatic aerial triangulation using four triangulation software packages, Z/I Imaging's MATCH-AT (ISMAT) and ISAT, LH Systems’ MST and VirtuoZo AAT, are presented. For the comparison of the results of the tie point extraction and the bundle block adjustment for triangulation, a sub-block from the Uster block in Switzerland was selected and used. Differences between these software packages are discussed with respect to their functionality and performance in detail. The achieved standard deviation of image coordinates varies between 0·2 and 0·5 pixel for the systems tested. The more signalised control points and check points to be used, the better the σ0 estimate which could be expected. The average number of extracted tie points varied from system to system with respect to the matching method and the resolution of the images used in the programs. The digital aerial triangulation of the Uster sub-block was faster than analytical triangulation and the elapsed time for triangulation of one image using different systems varies between about 0·5 and 6 min. Nevertheless, results also show that automated aerial triangulation is still prone to error in all systems. Image matching produces many blunders, which can only be handled efficiently by using a sophisticated blunder detection procedure, as is available with robust estimation. This is not the case for all the systems tested, however. There still remains a lot to be done in terms of development (improvement of matching, for example, by integrating robust estimation for error detection at an early stage, implementation of on-line triangulation, better internal quality control procedures, more transparent and simple user interfaces and more useful information for the user with better software manuals). However, it was shown that automatic aerial triangulation provides higher redundancy and reliability of results and much more economical photogrammetric practice than ever before.

Notes: The Photogrammetric Society was formed in 1952. The Council of the Society considered that the twentieth anniversary was a good point at which to record the events which led to its formation and the significant occasions and decisions which have taken place since 1952. Consequently, Paul Lamboit was invited to compile this History. He has placed the birth and development of the Society within the national and international photogrammetric context and his record of the deliberations which took place between 1947 and 1952 will be of particular interest to historians of our subject.This account was first published in a limited edition in 1971. Sufficient interest has since been expressed to prompt a wider circulation through publication in the Photogrammetric Record.The author served the Society continuously in several official capacities from 1953 to 1969 and he was elected to Honorary Membership in 1969.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméLa Photogrammetric Society a été fondée en 1952. Excellente occasion pour faire le point qu'un vingtiéme anniversaire, a estimé le Conseil de la Société; pour rappeler les circonstances de sa naissance, les étapes de sa croissance et les décisions importantes prises depuis 1952. Ce qu'on invita Paul Lamboit à faire. Son exposé resitue la naissance et le développement de la Société dans le contexte national et international de la photogrammétrie; la relation qu'il fait des décisions prises entre 1947 et 1952 intéressera particulièrement ceux qui s'occupent d'histoire de la photogrammétrie.Ce rapport d'abord publié en édition limitée en 1971, a suscité un intérêt suffisant pour que l'on se presse en le publiant dans le Photogrammetric Record de le porter à la connaissance d'un plus large public.L'auteur a exercé différentes fonctions de 1953 à 1969 dans l'appareil de la Société. Il a étéélu membre honoraire en 1969.〈section xml:id="abs1-3"〉〈title type="main"〉Zusummenfussung1952 wurde die Britische Gesellschaft für Photogrammetrie gegründet. Der Rat der Gesellschaft erwog, dass der zwanzigste Jahrestag eine günstige Gelegenheit sei, um die Ereignisse, die zur Gründung der Gesellschaft führten sowie die bedeutenden Veranstaltungen, die stattfanden und die Entscheidungen, die getroffen wurden, darzustellen. Aus diesem Grunde wurde Paul Lamboit eingeladen, diesen historischen Rückblick zu schreiben. Er hat dabei die Gründung und die Entwicklung der Gesellschaft in den nationalen und internationalen photogrammetrischen Zusammenhang gestellt nd sein Bericht über die zwischen 1947 und 1972 erfolgten Beratungen wird für an unserer Sache interessierte Historiker sehr aufschlussreich sein.Diese Zusammenstellung wurde erstmals in einer begrenzten Auflage im Jahre 1971 veröffentlicht. Genügend Interesse wurde inzwischen bekundet, um eine weitergehende Verteilung mit Hilfe des Photogrammetric Record zu veranlassen.Der Autor diente der Gesellschaft kontinuierlich in verschiedenen Ämtern von 1953 bis 1969, wo er aum Ehrenmitglied gewählt wurde.

Notes: Architecture at the Maya archaeological site of Uxmal in Yucatan, Mexico has been documented since the 17th century by historians, archaeologists, illustrators, photographers, and most recently photogrammetrists. This paper reviews the work of the major contributors to recording of architecture at Uxmal with a particular focus on the 19th century stereophotography of Alice and Augustus Le Plongeon who worked to record all the standing architecture at Uxmal, and the close range stereophotogrammetric projects that recorded the Adivino Pyramid during the late 20th century.

Notes: This article presents a complete mathematical model, which translates discrepancies between two orthophotographs created from different photographs, into precise corrections of the Digital Elevation Model (DEM). These corrections are the differences from the real surface and, if applied over the existing DEM, can produce a more accurate one. The mathematical model is straightforward, and is not approximate, and therefore there is no need for iterations.Possible applications include checking of automatically created DEMs, refinement of existing DEMs using aerial photographs and update of orthophotographs based on the previous DEM and new imagery.

Notes: A scholarly account of the formative discussions, the founding and the first 20 years of the Photogrammetric Society was published in 1971 and republished in 1974. This present review concentrates on the latter years of the life of the Photogrammetric Society prior to its merger with the Remote Sensing Society in 2001.The authors joined the Photogrammetric Society in 1960 and were conspicuous in its affairs for many years. Although both occupied the Society's presidential chair, they also fulfilled several other roles in its efficient management. Atkinson's first contribution to the Photogrammetric Record was published in 1968 and Newton's in 1971.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn a publié en 1971 un compte-rendu détaillé des 20 premières années de la “Photogrammetric Society”, à commencer par les discussions qui présidèrent è sa fondation. Ce récit fut republié en 1974. On se focalise dans cet article sur les dernières années d'activité de la “Photogrammetric Society” qui aboutirent à sa fusion avec la “Remote Sensing Society” en 2001.Les deux auteurs adhérèrent à la “Photogrammetric Society” en 1960 et y furent d‘éminents animateurs pendant de nombreuses années. Tous deux occupèrent le poste de président de cette Association mais remplirent égulement plusieurs autres fonctions qui contribuèrent à une gestion efficace. La première intervention d'Atkinson dans le Photogrummetric Record remonte à 1968, et celle de Newton à 1971.〈section xml:id="abs1-3"〉〈title type="main"〉ZusummenfussungEine wissenschaftliche Abhandlung über die Diskussionen zur Gründung, die Gründung selbst und die ersten 20 Jahre der Photogrammetrischen Gesellschaft wurde in 1971 publiziert und in 1974 wiederholt. Dieser aktulle Rückblick konzentriert sich auf die darauffolgenden Jahre der Photogrammetrischen Gesellschaft bis hin zur Vereinigung mit der Gesellschaft für Fernerkundung in Jahre 2001.Die Autoren wurden 1960 Mitglieder in der Photogrammetrischen Gesellschaft und trugen viele Jahre massgeblich zu deren Aktivitäsidenten der Gesellschaft auch verschiedene andere Aufgaben im Management wahrgenommen. Der erste Beitrag von Atkinson im Photogrammetric Record erschien 1968, der erste von Newton in 1971.

Notes: The determination of the attitude, the position and the intrinsic geometric characteristics of the camera is recognised as the fundamental photogrammetric problem. It can be summarised as the determination of camera interior and exterior orientation parameters, as well as the determination of 3D coordinates of object points. The term “exterior orientation” of an image refers to its position and orientation related to an exterior (object space) coordinate system. Several methods can be applied to determine the parameters of the orientation of one, two or more photos. The orientation can be processed in steps (as relative and absolute orientation) but simultaneous methods (such as bundle adjustments) are now available in many software packages. Several methods have also been developed for the orientation of single images. They are based in general on geometric and topological characteristics of imaged objects.This paper presents a survey of classical and modern methods for the determination of the exterior parameters in photogrammetry, some of which are available as software packages (with practical examples) on the Internet. The methods presented are classified in three principal groups. In the first. a selection of approximate methods for applications that do not require great accuracy is presented. Such methods are also used to calculate values required for iterative processes. In the second group, standard point-bused methods derived from collinearity, coplanarity or coangularity conditions are briefly reviewed, followed by line-based approaches. The third group represents orientation methods based on constraints and on concepts of projective geometry, which are becoming of increasing interest for photogrammetrists. In the last section, the paper gives a summary of existing strategies for automatic exterior orientation in aerial photogrammetry.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméLa détermination de l'attitude, de la position et des caractéristiques intrinsèques de la chambre photographique constitue un problème fondamental en photogrammétrie. Il se résume à la détermination des paramètres de l'orientation de la chambre de prise de vue (paramètres des orientations externe et interne), ainsi qu'à la détermination des coordonnées 30 des points de l'objet. L'orientation externe se rapporte à la détermination de la position et de l'orientation d'une chambre par rapport à un système externe de coordonnées. Différentes méthodes peuvent être utilisées pour calculer les éléments dorientation externe d'une photo, d'un couple ou de plusieurs photos. Le calcul de l'orientation peut être réalisé par étapes (par exemple les orientations relative et absolue) mais les méthodes simultanées (la compensation par faisceaux par exemple) sont actuellement proposées dans la plupart des logiciels. Plusieurs méthodes ont aussi été développées pour l'orientation d'images isolées. Ells sont basées en général sur les caactéristiques géométriques et topologiques des objets photographiés.Dans cet article on présente un ensemble de méthodes classiques et modernes pour la détermination des paramètres de l'orientation externe, certaines d'entre elles étant téléchargeables sous la forme d'applications sur Internet. Les méthodes présentées sont classées en trois groupes principaux. Le premier groupe contient une sélection de méthodes approximatives utilisées d'habitude quand une grande précision n'est pas exigée, ou encore pour calculer des vuleurs approchées des paramètres extrinsèques requises pour les méthodes itératives rigoureuses. Dans le deuxième groupe, on rappelle brièvement les jondements des méthodes basées sur les conditions photogrammétriques fondamentales (la colinéarité, la coplanéité et la coangularité). Dans ce groupe, les méthodes basées sur l'extraction des points ou des lignes sont également abordées. Le troisième groupe traite des méthodes d'orientation basées sur les contraintes et les concepts de la géométrie projective, de plus en plus utilisées par les photogrammètres. Le dernier paragraphe se rapporte aux méthodes destinées à automatiser le calcul de l'orientation externe en photogrammétrie aérienne.〈section xml:id="abs1-3"〉〈title type="main"〉ZusummenfussungDie Bestimmung der Neigung, der Position und den geometrischen parametern der Kamera wird als das fundamentale Problem der Photogrammetrie angesehen. Es kann zusammenfassend sowohl als die Bestimmung der Parameter der inneren und äusseren Orientierung der Kamera angesehen werden, als auch als die Bestimmung von 3D Koordinaten von Objektpunkten. Der Ausdruck “äussere Orientierung” eines Bildes bezieht sich auf die Lage und Orientierung bezogen auf ein äusseres (Objektraum-) Koordinatensystem. Es können verschiedene Methoden angewandt werden, um die Parameter von einem, zwei oder mehreren Bildern zu bestimmen. Die orientierung kann in Schritten erfolgen, was als Relative und Absolute Orientierung bezeichnet wird, aber auch simultane Methoden, wie die Bündelausgleichung, sind in vielen Softwarepaketen implementiert. Es wurden auch Methoden für die Orientierung von Einzelbildern entwickelt, die geometrische und topologische Eigenschaften der abgebildeten Objekte nutzen. In diesem Beitrag wird Beitrag wird eine Studie klassischer und moderner Methoden der Photogrammetrie zur Bestimmung der Parameter der äßeren Orientierung vorgestellt, wovon einige in Softwarepaketen zur Verfügung stehen, die von praktischen Beispielen im Internet ergänzt werden. Die untersuchten Methoden werden in drei Hauptgruppen eingeteilt. In einer ersten Gruppe werden Näherungslösungen vorgestellt, die für Anwendungen mit geringen Genauigkeitsanforderungen geeignet sind. Diese Methoden werden ansonsten für die Näherngswertberechunggen für iterative Prozesse verwendet. IN der zweiten Gruppe werden zuerst die punktbasierten Standardmethoden vorgestellt, die von Bedingungen zur Kollinearität. Koplanarität und Kowinkligkeit abgeletet sind. Danach folgen linienbasierte Ansätze. Die dritte Gruppe umfasst Orientierungsmethoden, die auf Zwangsbedingungen und auf Konzepte der projektiven Geometrie aufbauen, die für Photogrammeter von zunehmendem Interesse sind, Im letzten Abschnitt wird eine Zusammenfassung existierender Strategien für eine automatische äussere orientierung in der Luftbildphotogrammetrie gegeben.

Notes: The aim of this paper is to offer regional evidence from Spain on alcohol abuse among adolescents. Specifically, we identify the determinants of the decision to abuse alcohol with respect to the five most important regions of Spain, as well as for the country as a whole. To this end, we estimate Probit specifications using data drawn from the Spanish Surveys on Drug Use in the School Population corresponding to 1994, 1996 and 1998. The results first reveal patterns that are qualitatively similar, but quantitatively different. Similarly, it would appear that economic policies aimed at reducing the access of adolescents to alcohol may have a positive effect on reducing abuse. Finally, the results suggest that encouragement be given to healthy habits among young people, as well as to the fight against education failure and the launching of information campaigns that accurately portray the current lifestyle of adolescents.

Notes: The aim of this study was to determine the knowledge and acceptability of soymilk (defined as consumption pattern/usage and taste) by adult consumers, residing in different socio-economic areas (low vs. high) in Cape Town. The study population of 214 participants were selected using convenience sampling. A questionnaire was developed in order to obtain demographic data (four items); basic general knowledge of soymilk (four items); and acceptability of the tested products (consumption patterns and taste) (eight items). There was a significant difference between the two groups (P = 0.000) regarding basic knowledge of soymilk, with significantly more in the high socio-economic area (HSEA) having a score of at least 75%. Gender (P = 0.082) and age (P = 0.122) did not have a significant impact on the consumption patterns of soymilk. There was no significant difference between the two groups with respect to current usage (P = 0.228) and frequency of use (P = 0.213) of soymilk. However, a significantly smaller group (P = 0.000) of participants in the low socio-economic area had previously tasted soymilk compared with those in the HSEA (16.7% vs. 41.5%; P = 0.000). In conclusion, socio-economic status appeared to be associated with knowledge of soymilk. No significant differences with regard to gender, age or current usage in the two groups studied were noted.

Notes: ‘Development’ and the globalization of consumption is leading to a breakdown of biological and cultural diversity, erosion of food security, an increase in violence and devastation for the global biosphere. We urgently need to shift away from economic globalization and homogenization towards localization and diversification.

Notes: The promises and pitfalls of agricultural biotechnology have long been debated. The public is often thwarted because consumers frequently perceive as risky, and therefore undesirable, those advances that they do not understand or of which they are unaware. A comparative study of the introduction of a biotechnology innovation in the United States (US) and in the European Union (EU) is a case in point. In the US, despite concerns of consumer protection and environmental groups that the use of genetically produced growth hormone in milk-producing cows will adversely impact the safety of the milk supply, scientific evidence and governmental findings appear to indicate that milk from treated cows is identical in quality, taste and nutritional value to milk from untreated cows. Experience to date in the US demonstrates some consumer resistance to milk from those cows that have received the growth hormone, which typically leads to a 10% increase in milk production. In fact, if there is no perceived differentiation between the two forms of milk, the issue offers little choice to consumers at large, and may result in economic benefit only to selected dairy farmers, as well as the producers of the genetically produced growth hormone. This situation in the US is an example of dysfunctional technology transfer, with perceived desirable benefits to a few, and perceived undesirable benefits to society-at-large. The information suggests that the US may have reacted hastily in approving the use of bovine growth hormone in milk-producing cows. The EU has taken a divergent approach by enacting moratoriums against its use. The differences identified in this study, contrasting responses to the bovine somatotrophin issue in the US and EU – driven in part by general consumer attitudes towards biotechnology – may provide insights into the issues and challenges that will be faced by both advocates and opponents of global proliferation of certain advances in biotechnology.

Notes: The purpose of this article is to describe how households in Novgorod the Great, Russia, deal with food provision in everyday life. The study focuses on changes experienced in food provision and consumption in Russian society, in order to illustrate how households respond to the transformation towards a market economy. The study reflects women's perspective on food provision. Students from Novgorod the Great visited 105 households and asked the women in the household to answer a questionnaire. Results from the study show that in order to cope with changes in society related to economic reforms, Russian households had changed both their food consumption and food production patterns. There was no big difference between urban and rural households. Nearly all of the households were self-sufficient in the provision of vegetables and potatoes. Many households had a ‘dacha’ (plot), where they produced most of what they needed. Among the changes experienced during recent years (i.e. during the end of the 1990s), a decade after perestroika was initiated, households mentioned the rise in food prices and the decrease of income. Households reported that they consumed less fruit and/or meat. Some households also mentioned that the quality of nourishment had decreased, thereby indicating lower general quality, lower nutrition value, or less healthy foodstuffs.

Notes: Localization: A Global Manifesto. Ed. by Colin Hines (2000). London. Published by Earthscan Publishing. ISBN 1-85383-612-5 (softcover). In Canada, the book is available from for Can$29.00. In the UK, the book is available at for £10.99 or earthinfo@earthscan.co.uk

Notes: SYNOPSIS. Ten new species of colorless Eugleninae are described. One of them is the type of a new genus (Calycimonas physaloides nov. gen. nov. sp.). Especially remarkable forms are: Astasia acus, a species related to the green Euglena acus but without chromatophores and stigma and considerably smaller; Astasia edax, a species with animal-like nutrition and peculiar ecological adaptations; Petalomonas striata, a form which is not spirally but transversely striated; and finally Hyalophacus caecus, which was observed already by Klebs and Pochmann but was not sufficiently described. The new genus Calycimonas (ex fam. Peranemacearum) is related to Tropidoscyphus on the one hand (nearly the same shape as e.g. Tr. octocostatus, but possessing only a single flagellum) and to Petalomonas on the other hand (mode of nutrition and of swimming, formation of the reservoir, rigidity: however in transverse section not flattened).The Astasiae with zootrophic nutrition are collected in a new subgenus Astasiae devorantes or Phytophaga which comprises besides A. edax three species already described by Skuja.

Notes: SYNOPSIS. H. canis (James) is reported from three of 36 stray dogs at Singapore and one of 34 palm civets (Paradoxurus hermaphroditus Pallas) from Jeram, Selangor. H. muris (Balfour) was found at Singapore in 10 of 61 examples of Rattus norvegicus (Erxleben) and five of 23 of R. rattus diardi (Jentinck), and is also recorded from six of 139 examples of R. r. jarak (Bonhote) from Pulau Jarak, Straits of Malacca. Neutrophils of P. hermaphroditus containing gametocytes of H. canis exhibit pronounced karyorrhexis, while most of the parasites themselves show signs of pyknosis.

Notes: SYNOPSIS. A total of 155 clones of Stylonychia putrina collected in nature were tested for mating type. Two sexually isolated varieties were found among them: Variety I with 12 mating types and Var. II with 11. Five of the clones isolated in the laboratory belonged to 3 additional mating types of Var. I making a total of 15 mating types in this variety.Crosses were made among 6 of the mating types of Var. I, and 114 clones of progeny were raised and tested for mating type. No simple genetic explanation of the results was evident.An abnormal type of conjugation with fusion of the conjugants and subsequent fission was studied. Both parental mating types sometimes segregated during the first two fissions of a fused animal. Mating type determination in the progeny of the fused animals seemed to parallel that of the progeny of the normal conjugants in that in both cases certain mating types tended to be dominant over others.

Notes: SYNOPSIS. The cytochemical procedure of Sen was used to demonstrate urease activity in Tetrahymena pyriformis S.

Notes: SYNOPSIS. The chimpanzee is shown to behave like man to infection with Babesia divergens or bovis: the intact animal is totally resistant, whereas the splenectomized animal develops a fulminating infection accompanied by blackwater. The splenectomized rhesus monkey reacts in the same way also, but splenectomized rabbits are insusceptible. In the chimpanzee the typical accolé position of the “divergens” organisms (as seen in cattle) is absent, but occurs in the rhesus. It is suggested that latent piroplasmosis in man may exist on a large scale in rural populations in infected localities.

Notes: SYNOPSIS. Studies cf 3 conjugating strains of Tetrahymena pyriformis grown in a bacterized medium indicated the presence of a system of alternative immobilizing surface antigens. Each strain was found to have the potential for the expression of 3 serologically unrelated antigens. These consisted of a “high temperature” antigen (expressed in the range of 20–35d̀C), a “low temperature” antigen (exhibited in cultures at 10d̀), and an antigen induced by growth in the presence of the above-mentioned “high temperature” antiserum. Normally, by the immobilization reaction, only one of these antigens could be detected as present on any one organism at any given time. The “high temperature” antigens of two of the strains were serclogically related while that of the 3rd strain did not cross-react with antisera to the other two. The “low temperature” antigens of the 3 strains were serologically related as were the antigens induced by growth in antiserum.Studies of inbred hybrids of two of the strains indicated a potential for still more alternative antigens as well as for the spontaneous expression of the antigen which in the parental strains could only be induced to appear by the presence of the specific antiserum.Study of the 3 strains in axenic medium indicated the existence of a more complex system and the possibility that two or more immobilizing antigens may be present simultaneously.

Notes: SYNOPSIS. The establishment of Eimeria tenella sporozoites in the cecal mucosa of the chicken is described. The invasion process was similar to that reported for E. necatrix by Van Doorninck and Becker. Sporozoites were found to pass through the surface epithelium of the cecal mucosa into the lamina propria. Within the lamina propria the sporozoites were engulfed by macrophages and transported to the cells of the glands of Lieberkühn. Development of the sporozoites ensues within the gland epithelium.

Notes: SYNOPSIS. The morphology of the vegetative phase and the sexual process in Pandorina morum have been studied in detail under controlled laboratory conditions. A number of strains from various areas of the United States, all essentially indistinguishable on morphological grounds, were analyzed for sexual compatibility. Forty-seven heterothallic clones were found to represent 15 separate pairs of mating types, or a minimum of 15 syngens (sensu Sonneborn, 1957). Two clones proved to be homothallic. Nine additional clones, which were not observed to mate with any strain, can be classified only after further collecting. The separate heterothallic pairs of mating types are sexually isolated by factors acting at the stage of gamete production; incompatible mating types produce no gametes when they are mixed together. The geographical distribution of the sets of mating types is very incompletely defined as yet, but they are not strictly endemic forms. Thirty heterothallic strains, representing each of the 15 sexually isolated sets of mating types of Pandorina morum, have been deposited with the Culture Collection of Algae maintained at Indiana University, Bloomington, Indiana, U.S.A.

Notes: SYNOPSIS. When grown in CPLM medium or in a similar medium containing glucose instead of maltose as its sugar, Tritrichomonas foetus, Strain O, was much more sensitive to injury when frozen to -21d̀ C. in the presence. of 1 m glycerol during the initial and logarithmic phases of its population growth curve than at its peak and for some time thereafter. In 7 experiments in which the population peak occurred an average of 28.1 hours after inoculation, the average culture age at which the protozoa first survived freezing was 20.3 hours, at which time the population had reached 52.6% of its peak. The optimum culture age for survival after 1 day of freezing averaged 37.7 hours at which time the population averaged 75.6% of its peak. The optimum culture age for survival after 7 to 15 days of freezing averaged 32.3 hours, at which time the population averaged 82.7% of its peak. Better survival upon freezing was obtained in those experiments in which the population peak was reached relatively rapidly.

Notes: SYNOPSIS. Specimens of Blepharisma undulans were transferred from young clone cultures to a rotocompressor with 3 mm3 of culture medium. The organisms were slightly compressed and photographed at various intervals with dark field illumination. The sequence of macronuclear and cytoplasmic changes was compared with similarly followed Feulgen preparations.The cycle falls into several phases: (1) an interphase (12–24 hr.) in which the organism increases in size while cytoplasmic and macronuclear appearances remain unchanged. During this phase, the macronucleus consists of 3 to 5 nodes of various sizes connected by strands. (2) a pre-condensation phase (1 hr.) in which a new posterior peristome and cytopyge appear without visible macronuclear change. (3) a condensation phase (10–20 min.) in which the macronuclear nodes coalesce into a round mass without dissolution of the central nodes or strands. (4) a postcondensation phase (1 hr.) characterized by: (a) elongation of the condensed macronucleus into a rod-like shape followed by typical nodal formation; or (b) elongation of the condensed macronucleus into a form resembling the letter “J”, followed by nodal formation, and resulting in a double row of nodes in one daughter and a single row in the other. Separation occurs at this time, initiating the new interphase. The development of the j-form macronucleus. the lack of obliteration of the central nodes, and the characteristic interphase condition distinguish this strain of B. undulans from others described elsewhere.

Notes: SYNOPSIS. Six species of astomatous Infusoria, 4 new, are described from the alimentary tract of Oligochaeta from Ochrida Lake. Two belong to Ochridanus, characterized by a cytoskeleton whose “V”-shaped basal piece bears on its branches two articulated hooks brought together by a skeletal blade. This genus found in Ochridanous Tubificidae represents the counterpart of Anthonyella in the Lumbriculidae of Lake Baïkal. The presence of Ochridanus in these worms concurs with the almost complete absence of representatives of Radiophrya of which we have found but one species. A species of Metaradiophrya, a genus unknown to date from the Lumbricidae, was noticed in Glossoscolecidae. The different species of Ochridanus, Anthonyella, Metaradiophrya, and Radiophrya compose a very homogeneous group of Radiophryinae. The study of the ciliary rows and the cytoskeleton of 2 species of Juxtaradiophrya, parasitic in the Lumbriculidae of Ochrida, shows that, in the morphology of these ciliates, as well as in the same forms from Lake Baïkal, many transition characteristics exist between the Radiophryinae and Hoplitophryinae or Mesnilellinae. These 3 sub-families, with their undeniable genetic kinship give coherence to the family Hoplitophryidae.

Notes: SYNOPSIS. Histochemical techniques were used to demonstrate the intracellular distribution of some hydrases, hydrolases, oxidases, and dehydrogenases in Stylonychia pustulata. The hydrase, aconitase, was confined to the mitochondria. Zymohexase activity occurred in the cytoplasm and probably in the mitochondria. The hydrolases, acid and alkaline phosphatases, lipase, and urease, were localized in the mitochondria. Lactic and glutamic dehydrogenases were confined to the mitochondria. Peroxidase and glycerophosphate dehydrogenase were absent.

Notes: SYNOPSIS. When two strains cf T. pyriformis that do not require exogenous pyridoxine are crossed, all progeny grow without the vitamin. Offspring from crosses of two pyridoxine requiring clones require pyridoxine with the exception of a few which will grow without pyridoxine. The ratio is approximately 3:1 favoring the pyridoxine requiring category. In matings involving the homozygous dominant pyridoxine requiring clones with the double recessive mutant, that is +/+ X p/p, all of the resulting progeny need pyridoxine. Test crossing these heterozygotes (+/p) with the parental pyridoxine non-requiring clones (p/p) gives offspring approximating a 1:1 ratio. Matings between two heterozygotes derived from breeding experiments also yield progeny in approximately 3 pyridoxine requiring: 1 pyridoxine non-requiring. All data indicate selection for the heterozygote in the population and a possible selection against either homozygote. The great abundance of heterozygotes and rarity of recessive homozygotes in natural habitats corroborates these findings. The genetic evidence supports a single gene hypothesis although the possibility of multiple closely linked genes cannot be ignored. There is also the possibility that a dominant suppressor gene may function in blocking the activity of the pyridoxine mutant genes. Moreover, if this gene exists it may be incompletely dominant since the heterozygote grows slightly on deficient media.

Notes: SYNOPSIS. Trichodina urinicola was found in newts, Triturus cristatus and T. taeniatus, in three localities in Czechoslovakia. The ciliate populations showed important differences on the basis of which they were separated as three new forms of this species: T. urinicola f. typica, T. urinicola f. bohemica, both from Triturus cristatus, and T. urinicola f. taeniatus from Triturus taeniatus. The great variability of trichodinids is evident from the literature as well as from our own observations, so that these new forms are to be regarded as provisional ones until it is possible to decide on the basis of a large number of observations the extent of specificity and variation of individual endozoic species of Trichodina. A detailed description of these forms is given as well as a comparison with the known species of trichodinids inhabiting the urinary tract of amphibians. A brief comment on the present taxonomy of the Urceolaridae in general is outlined.The need for a uniform description of these ciliates is emphasized; in connection with this, the taxonomic value of individual body characters is discussed. Special attention is paid to the adhesive disk of Trichodina, the structure of which is of greatest importance in the taxonomy of this group. On the basis of Dogel's and Fauré-Fremiet's descriptive methods employed in study of trichodinids, a proposal of a uniform description of Trichodina is made which involves all the important features of these protozoa.

Notes: SYNOPSIS. Several substrains of Euglena gracilis var. bacillaris made chlorotic by treatment with pyribenzamine or streptomycin, or by growth at high temperature (35–36°C.), have been examined for their carotenoid content. They differ from the normal green strain both qualitatively and quantitatively. Some strains produce no detectable carotenoids while the carotenoid concentration in the strains producing most is at best only one-fifth that of the normal strain. In all substrains producing carotenoids, the carotene fraction consists of β-carotene accompanied by some members of the phytofluene series. In only two of these substrains, HB-G and PBZ-G3, are xanthophylls produced in significant amounts. In HB-G, the main pigment is echinenone, and in PBZ-G3 it is zeaxanthin. The significance of these findings is briefly discussed.

Notes: SYNOPSIS. Association of gamonts of Pyxinia crystalligera takes place in the midgut of its beetle host, Dermestes vulpinus. At 25°C. the development of gametocysts to the point of liberation of sporocysts is completed between about 15 hours and 27 hours after the gametocysts are deposited with fecal material. Dehiscence is favored by relative humidities of 0% to 90%, but is not favored by a relative humidity of 100%. During the early development of the gametocysts outside the host, the crystals and paraglycogen granules in the cytoplasm of the associated gamonts become concentrated in large masses. The gametes are formed at the periphery of the gamonts. After fusion of the gametes takes place and the sporoblasts begin to develop, the residual cytoplasm containing the inclusions moves outward to form a continuous layer next to the gametocyst envelope, so that the sporoblasts become crowded into a central core. A few hours before dehiscence is initiated a clear area appears on the upper side of the gametocyst. The contents of the gametocyst begin to shrink away from the envelope except in the region of the clear area. Eventually the sporocysts emerge through the clear area and press against the envelope of the gametocyst, causing formation of a conical papilla in the envelope. With continued pressure from the sporocysts, the papilla ruptures at its tip, and the sporocysts emerge in a continuous thread until dehiscence is completed. The thread of sporocysts may attain a length of about 11 mm.

Notes: SYNOPSIS. The steps leading to purine ring closure were examined in Strigomonas oncopelti. The flagellate has an obligate adenine requirement (hypoxanthine and guanine are inert) when grown without p-aminobenzoic acid. The imidazole counterpart of adenine but not the imidazole counterpart of hypoxanthine was active. A pathway for purine biosynthesis compatible with these results is sketched.

Notes: SYNOPSIS. The Nuttallia of the gerbil is transmitted by Rhipicephalus secundus only if the infected meal is taken by the larva, and the subsequent nymphal stage is the only one which is able to infect. There is no transovarial transmission.Infective trophozoites remain in the larval caeca for about 12 hours after gorging. The infective nymph is able to give rise to new infections at various times after it has been allowed to feed, but never later than the third day after disengagement from the host.

Notes: SYNOPSIS. The process of autogamy in unassociated individuals of Paramecium polycaryum was reported by the author in 1954. In May, 1955, conjugation was first seen in this species in cultures collected by me at Annamalainagar, South India, thus removing it from the list of non-conjugating species. This appears to be the first instance in which the process of autogamy was detected prior to observation of conjugation in the same species. Autogamy occurs in singles of the Indian race and appears to be similar, cytologically, to that of American races. The details of the micronuclear behavior in conjugation parallel those of autogamy in singles. In fact, the conjugation process seems to be one of double autogamy (cytogamy), rather than of reciprocal gametic interchange. Paroral cones, often of fair size, are formed but breakdown of the cones to permit micronuclear passage has not been observed. In conjugation there are the usual three pregamic divisions; the first shows four characteristic crescents. The resulting nuclei may all participate in the second division. Fertilization occurs in the paroral cone area. Frequently, separation of the conjugants takes place immediately after the first division of the synkaryon. The old macronucleus undergoes very little change prior to the last postzygotic micronuclear division in the ex-conjugant, when it goes into a skein condition. Four macronuclear and four micronuclear anlagen are formed in the ex-conjugants at the completion of reorganization. On occasion giant individuals of P. polycaryum were observed to have ingested numbers of Tetrahymena pyriformis. The presence of an unidentified rod-like organism in the cytoplasm of the paramecia (non-conjugating) was detected in one collection from Bangalore, India.

Notes: SUMMARY. The mating behavior of 16 stocks of Paramecium multimicronucleatum from 12 states has been studied. Mating always follows a decline in nutritive conditions. The evidence indicates that there exists one set of four interbreeding mating types. The period of subculture strongly influences the mating reactions, many stocks mating only long after isolation from nature and culture in the laboratory under the restricted conditions employed. Selfing was observed to occur in many races, usually after long periods of subculture. It first occurred in only a small proportion of the population, later in a larger proportion. The similarities and differences between P. multimicronucleatum and other species of protozoa showing multiple mating types are discussed.

Notes: SUMMARY. A study of the temperature-pressure relationship in oxygen poisoning of Paramecium caudatum was undertaken, as the initial step in defining some of the major factors in in vivo oxygen poisoning. Paramecium was selected because it was relatively simple to culture in a pureline clone, large numbers were readily obtained, and it was large enough to be clearly visible under low magnification. The protozoa were exposed to oxygen pressures of 0 (100%), 15, 30, 45, 60, 75, 90, 105, 120 pounds/inch2 gauge pressure at each of the following temperatures: 1, 5, 10, 15, 20, and 27°C. Exposure was accomplished in a transparent, high-pressure lucite tank which permitted visual observation with aid of a dissecting microscope. It was found at temperatures above 5°C. that oxygen toxicity varied directly with pressure, but below this temperature, with oxygen tensions of 1–2 atmospheres (absolute), oxygen toxicity varied inversely as the temperature. The possibility is advanced that oxygen may be affecting two cellular processes (perhaps enzymatic), one of which is temperature-limited below 5°C. and would, therefore, decrease the death time as the temperature is decreased. Several experiments performed at 3°C. produced a death time intermediate between results obtained at 1° and 5°C.

Notes: SUMMARY. A stock of Paramecium bursaria is described in which the peniculus contains only 8 columns of cilia and associated “granules”. The gullet system is composed of organelle complexes almost exclusively, and incorporates no underlying or transecting extensions of “pellicular fibrillar systems”. A brief discussion is presented on the value of the peniculus as a taxonomic criterion in separating “aurelia” and “bursaria” groups in Paramecium.

Notes: SUMMARY. Strains E, S and W of Tetrahymena pyriformis were examined for their ability to carry out the reactions of the Krebs-Henseleit urea cycle, using growth and enzyme studies. None of the strains was able to grow on either citruliine or ornithine in place of arginine, and proline was as active as citrulline or ornithine in sparing arginine. So little citrulline or arginine was synthesized by cell-free preparations as to be of no significance in the growth or nitrogen metabolism of the ciliates. Slight arginase activity could be detected in homogenates, but no urea was found in cultures. No urease activity could be detected using urea-C14.

Notes: SUMMARY. An eimerian coccidian is described from the flying squirrel, Glaucomys volans, in Florida. It is identified as the same eimerian described by Roudabush from the flying squirrel in Iowa as Eimeria sciurorum. Evidence is presented that Roudabush incorrectly identified the organism. It is renamed as E. parasciurorum nov. sp. Mature oocysts have mean measurements of 29 × 16°, an index of 1.82, are cylindrical with rounded ends, have a dual membrane, and no extra residual body. Oocysts are without micropyle. Four egg-shaped, mature sporocysts in the oocyst have mean measurements of 11.2 × 6.2°, an index of 1.81, contain an oval, granular, intraresidual body and two pyriform sporozoites 10 × 3.2°, index 3.11.

Notes: SUMMARY. Two centrioles, an old one and a new one, are always present in the resting cell. From prophase onward two new ones and two old ones are present. Beginning with the resting stage, five types of centriole life cycles are described and compared with one another: In type 1, both centrioles are elongate; in type 2, the old one is long and the new one, which is short, elongates in prophase; in type 3, both are short, both elongate in prophase, and both, except for their anterior tips, degenerate in late telophase; in type 4, both are long but in prophase their distal ends become free of the rest of the centrioles, these ends migrate to center or posterior end of cell, where, after they produce the achromatic figure and it completes its function in nuclear division, they degenerate; in type 5, both are short and neither elongates at any stage of its life cycle.New centrioles are produced by the anterior ends of old ones. In their first generation, centrioles produce only extranuclear organelles (flagella, parabasals, axostyles, etc.); in their second and later generations, they produce only the achromatic figure (gametogenesis in Trichonympha and reorganization in Barbulanympha and Rhynchonympha are exceptions to this rule).The distal ends of centrioles in some types of cycles are surrounded by centrosomes; in others they are not. In one type of centriole life cycle a small central spindle is present in the resting cell in two genera; in the other types this is not the case.

Notes: SUMMARY. The endogenous development of the life cycle of Eimeria alabamensis Christensen, 1941, occurs in the nucleus of the intestinal cells of cattle. Calves were killed at various intervals after inoculation with infective oöcysts to study the endogenous cycle. Excysted sporozoites were found in the contents or scrapings from the walls of rumen, omasum, small intestine, cecum, and colon. They were found in the cytoplasm of intestinal epithelium at 2 days. Schizonts were found in the nuclei beginning at 2 days, but the number was low by the 8th day. Merozoite numbers usually ranged between 16 and 32. Some host nuclei contained as many as 48 or more, but these appeared to be the result of more than one schizont merging in the same host nucleus. Merozoites were slender, spindle-shaped bodies while still in the schizont walls, but were short with bluntly rounded tips when found in intracellular spaces and crypts. Gametocytes were found as early as the 4th day. Most of the stages of gametogenesis were limited to the lowest third of the small intestine, but in heavy infections some were also found in the cecum and upper colon. Microgametocytes were multinucleate and were more densely stained than the uninucleate macrogametocytes. The ratio of macrogametocytes to microgametocytes in 100 gametes was 78: 22. Oöcysis with “shells” were found in sections of the lower 20 feet of the ileum on the 6th day, which coincided with the shortest prepatent period reported previously. As many as three schizonts or microgametocytes or four or five macrogametocytes or oöcysts could be found in the same host nucleus. The variations in shape of the oöcysts appeared to be dependent on the number of oöcysts crowded into each nucleus.

Notes: SUMMARY. The role of centrioles in achromatic figure production is considered when the number present varies from 1–8. Each centriole after it becomes elongate produces astral rays from its distal end. Some of these rays remain free; some, by joining centromeres, become chromosomal fibers; and some, by joining and growing along those produced by one or more other centrioles, produce the central spindle portion of the achromatic figures. Thus, one centriole may function cooperatively with one to several others in the production of central spindles. But at least two centrioles must be present, and in the proper spacial relation to each other, to form a central spindle; one by itself can form only free astral rays, no central spindle or chromosomal fibers.The flagellated areas (to which the centrioles are anchored anteriorly) play an important role in determining the position of the distal ends of the centrioles with respect to one another, and the position of these ends, in turn, in a large measure, determines the types of achromatic figures produced, particularly the number of central spindles.

Notes: SUMMARY. Observations on binary fission of Lacrymaria olor show that it is a transverse fission. It involves probable intranuclear division of the micronucleus. Both micro- and macronucleus elongate in preliminary stages. Each is ultimately divided as cytoplasmic constriction cuts the spindle fibers of the former, and the connecting, nucleoplasmic thread of the latter.Surging movements of cytoplasm after fission elongate the daughter organisms and move new nuclei to normal, central sites. The anterior proboscis of the posterior daughter regenerates suddenly, complete with coronal cilia. Metachronal waves along ciliary meridians, strongly reversed on the posterior daughter, cause an oscillating movement which pulls the two apart, except for a slender, pellicular thread, ultimately severed. Until broken, this thread connects the rear tip of the anterior animal to the forward end of the proboscis of the posterior one. The organism is semi-quiescent, with proboscis retracted (except spasmodically) throughout fission. After fission the anterior animal quickly begins feeding movements and soon swims away. The posterior animal requires about half an hour before being able to begin feeding and swimming movements.The anterior contractile vacuole of the original animal becomes the primarily active vacuole of the anterior daughter; the posterior one that of the posterior daughter. Missing vacuoles are regenerated by the daughters in about one hour after fission. The division process requires about one hour for completion at 22.4°C.