ALBERT

Notes: Résumé Une méthode d'élevage deFormica polyctena est décrite, basée sur l'utilisation de deux nids, de types différents suivant l'été ou l'hiver. Ce sont les fourmis elles-mêmes qui adoptent l'un ou l'autre type suivant la saison. Le développement de la colonie y parait satisfaisant, sauf la procréation des sexués au printemps. L'observation continue des fourmis y est facile.

Notes: Résumé L'étude du microclimat existant dans le nid deCamponotus acvapimensis montre que les facteurs mesurés varient très peu au cours de l'année: la température moyenne est de 26±1° C. La variation annuelle de la température moyenne est de l'ordre du degré (Tm de 27° en saison sèche contre 26° en saison des pluies). L'atmosphère des cavités est continuellement saturée en vapeur d'eau (100% d'humidité relative à 27° C). Afin de maintenir ces conditions constantes les fourmis enterrent moins profondément leur nid en saison des pluies qu'en saison sèche. En période d'inondation, elles vont jusqu'à grimper avec leur couvain dans les herbes pour échapper à la noyade. Les conditions existant au niveau du sol de la savane non brûlée sont comparables à celles qui existent sur le sol des forêts galeries. De ce fait, la limite entre les milieux où les facteurs microclimatiques restent stables et ceux où ils varient fortement est située à la frontière qui sépare la savane brûlée de l'ensemble savane non brûlée-forêt galerie.

Notes: Résumé Deux expériences ont été faites sur l'importation et l'exportation d'eau par des colonies deMacrotermes natalensis (Haviland) Fuller. Dans la première expérience, de l'eau tritiée et un complexe chromium 51 versenate ont été injectés dans la nappe aquifère, vers 12 m de profondeur, à fin de suivre le mouvement de l'eau partant de la nappe aquifère jusqu'aux termitières surjacentes. Les résultats de l'expérience ne soutiennent pas l'hypothèse que les Termites remontent de l'eau de la nappe aquifère jusqu'à leurs termitières. Dans la seconde expérience, une ouverture a été faite dans chacune des trois termitières, et le sol humide apporté par les Termites pour boucher cette ouverture a été enlevé chaque jour pendant une période de six-sept semaines. D'après le poids du sol enlevé et l'humidité qu'il contenait, il a été possible de calculer que chaque colonie de Termites avait perdu environ 5 litres d'eau. Des calculs employant des mesures faites par un autre auteur sur la respiration indiquent qu'une colonie contenant un million deMacrotermes produit à peu près 4 litres d'eau par semaine, résultat d'activité métabolique. La perte d'eau provenant des termitières était done probablement contrebalancée par la prodution d'eau métabolique à l'intérieur des termitières.

Notes: Résumé L'hormone juvénile synthétique: 17% alltrans+83%trans, trans, cis-méthyle 10-epoxy-3,7,11-triméthyle-2,6 tridecadienoate et l'analogue de l'hormone juvénile: méthyle 10-chloro-3,7,11-triméthyle-2 dodecenoate et éthyle 10-epoxy-3,7,11-triméthyle-2,6-dodecadienoate, qui ont été administrés amenés sur papier filtre à de petits groupes de termitesReticulitermes lucifugus santonensis Feyt., ont causé une différenciation de larves et de pseudergates en présoldats et/ou intermédiaires pseudergate-soldat. A la différence du rapport de 1 soldat à 100–300 autres individus dans des colonies normales, on assiste sous l'effet de la substance testée avec effet d'hormone juvénile à l'apparition d'un grand nombre de soldats en surplus, dont le nombre peut même dépasser celui des autres individus. Le trouble de l'équilibre entre les castes conduit à un taux de mortalité supérieur des termites.

Notes: Résumé L'étude de la ponte des ouvrières de la Fourmi d'Odontomachus haematodes nous a permis de mettre en évidence les faits suivants: 10 Les \oeufs pondus par les ouvri\`eres donnent naissance \`a des m\^ales. 20 La quantit\'e d'\oeufs pondus par les ouvri\`eres orphelines est fonction du nombre d'ouvri\`eres de la colonie. a) La ponte d'ouvrières, mises en présence d'une ou de plusieurs reines, échappe au contrôle des reines lorsque les deux conditions suivantes sont réunies: - un effectif en ouvrières supérieur à 50 pour une reine; - un espace vital important. b) Dans tous les autres cas, la ponte des ouvrières est sous la dépendance, au moins partielle, d'une véritable phérormone. Cependant quelles que soient les méthodes utilisées (nids à «courant d'air», action d'extraits royaux, etc.) nous n'avons jamais obtenu, expérimentalement, une inhibition totale de la ponte des ouvrières. c) Nous pensons, par conséquent, que les reines inhibent la ponte des ouvrières grâce à: - une phérormone qui exerce une action retardatrice; - des stimuli sensoriels.

Notes: Résumé Cette publication communique les premiers résultats connus sur l'origine des sociétés des Fourmis voyageuses africaines du sous-genreAnomma. - Les populations d'Anomma ne possèdent jamais plus d'une reine fonctionnelle. - Une colonie privée de sa reine fonctionnelle ne forme pas une reine de substitution, n'adopte pas une reine étrangère. Elle s'éteint avec la mort de ses dernières ouvrières, en moyenne 27 jours après la dernière ponte de la reine. - La suppression d'une reine n'altère les activités (colonnes de chasse, terrassements, exodes) qu'indirectement, par l'extinction progressive de la population. - La méthode de la suppression de la reine vivante nous a permis d'étudier avec plus de précision les différentes phases du développement des ouvrières et des mâles. La durée moyenne œuf-imago est de 38 jours pour les ouvrières et de 58 jours pour les mâles. La vie moyenne adulte est respectivement de 27 et 10 jours. - Nous avons pu établir le fait de la ponte des ouvrières. Ces œufs donnent des larves mâles qui ne se développent pas très loin. - La scission d'une colonie et la formation d'une nouvelle reine sont liées à la présence d'un couvain mâle au stade nymphal. Toutefois, chaque couvain mâle n'occasionne pas nécessairement une scission et chaque scission n'implique pas une fondation. Il faut qu'en outre soient réalisées dans la population les stimuli trophallactiques requis pour un exode et la présence d'une jeune reine. - ChezAnomma, les mâles et les fondations se produisent durant toute l'année, mais avec une fréquence nettement supérieure pendant le dernier tiers de la saison sèche. Ce fait est en rapport avec les mauvaises conditions climatiques de la saison sèche. - L'origine des jeunes reines et les fondations se déroulent très probablement comme suit: • Un couvain mâle numériquement très inférieur à un couvain ouvrier, jouit d'un régime de suralimentation. Un œuf de la série encore fécondée évoluant dans ces conditions privilégiées, donnera, non pas une ouvrière, mais une reine. • Cette reine (ou éventuellement plusieurs) éclot au moment de la nymphose des mâles, une quinzaine de jours avant l'éclosion de ceux-ci. Avec les nymphes mâles elle polarise une partie de la population qui progressivement se détache du reste, polarisé autour de la reine fonctionnelle. Celle-ci effectue un exode dès que les conditions de son couvain sont déterminantes (éclosion massive d'ouvrières) et laisse dans l'ancien nid les ouvrières centrées autour de la nouvelle reine et du couvain mâle. Les nymphes mâles éclosent et essaiment. La jeune reine, fécondée, commence sa course de nouvelle reine fonctionnelle.

Notes: Résumé Ce travail a pour objet l'étude de fécondité des reines de la FourmiPlagiolepis pygmæa. Cette fécondité est pour ne grande part contrÓlée par les ouvrières, ainsi qu'on poeut le constater en faisant varier leur nombre, ou les conditions de leur alimentation. Les variations expérimentales de facteurs physiques tels que température, durée de l'hibernation, action du gaz carbonique sont ressenties par les reines dont la ponte est perturbée; nous avons montré que dans ces derniers cas, les facters considérés agissaient en grande paritie par l'intermédiaire des ouvrières dont ils modifient les possibilités physiologiques. La fécondité des reines est un fidèle reflet de l'état ophysiologique des ouvrières.

Notes: Résumé La fourmi dulotique obligatoirePolyergus rufescens (P. r.) est comparée histologiquement avec laRaptiformica sanguinea Latr. (R. s.) seulement facultativement social-parasitique. Dans les papilles rectales des deux espèces se trouve une zone avec Granulae, rangée sur fils de plasma. Une part des glandes deP. r. montre une dégénérescence: les glandes épinotales (glandes métathoraciques) manquent totalement, les glandes labiales sont diminuées largement, les glandes propharyngeales (gl. maxillaires) ont moins de cellules isolées que celles desR. s., les glandes mandibulaires et postpharyngeales (pharyngeales) ne montrent pas des dégénérescences. Les glandes maxillaires («glandes linguales», conformément àOtto, 1958) sont exactement décrites et illustrées. Leurs cellules isolées deP. r. sont plus nombreuses, comme celles deR. s. Quelques cellules glandulaires se trouvent dispersées près de la cuticule, spécialement près de la membrane articulée. Les glandes supplémentaires des deux espèces montrent des variations énormes dépendant de l'âge, qui sont regardées comme une transition de la phase de la sécrétion à une phase d'emmagasinage. En ce qui concerne les mesures de surface des corpora pedunculata qui sont regardés comme des centres particulièrement efficaces,R. s. est seulement un peu surclassée. On ne peut pas parler d'une dégénérescence deP. r. à cet égard. On a trouvé des organes en forme de reins dans le Prothorax desR. s.-♀ écloses à l'instant. Ces organes montraient une dégradation histologique. Il s'agit probablement de glandes prothoraciques de sécrétion intérieure. Après examen des organes sensoriels des antennes on ne trouvait pas une infériorité essentielle deP. r. en comparaison deR. s. Dans les organes génitaux des ♂♂, le Ductus éjaculatorius avec le dispositif d'accrochage peu connu ainsi que la bulle du pénis sont décrits et illustrés avant tout. Le cycle d'évolution des ♀ ovarioles, conformément àWeyer (1927) (Formica rufa), est aussi visible auprès deR. s., mais il se montre dans une forme diminuée seulement auprès des ♀. Dans le noyau chromatique de la plupart des organes on peut voir un développement montant des chromo-centres collectifs durant le vieillissement. Dans ce cas,R. s. a une avance à partir de l'éclosion, qui reste aussi chez les animaux plus âgés. Conformément à la terminologie deWhite (1943, 1945),P. r. est désignée comme microhétérochromatique etR. s. comme mégahétérochromatique. Des relations possibles et probables entre le parasitisme social et l'histologie des espèces étudiées sont discutées; en outre, les nouvelles constatations histologiques sont discutées.

Notes: Summary The air-earth current density in the stratosphere, the columnar resistance derived from the measurements of conductivity, and the ionospheric potential were investigated. The data were obtained by radiosonde ascents during the period of 1957–1967. It was found that the local horizontal visibility at the surface is related to the air-earth current density in the stratosphere, and it is expected that the air-earth current density has a seasonal variation. Statistical results show that indeed the air-earth current has a pronounced seasonal variation, high in winter and low in summer. The columnar resistance has also a seasonal variation, reverse to the variation of the air-earth current. The percentage time variation of the air-earth current (1/i) (di/dt) was found to be twice as much as the percentage time variation of the columnar resistance (1/R) (dR/dt) at the Tateno Observatory. The ionospheric potential, deduced from the measurements of the potential gradient by radiosonde ascents, shows no clear seasonal variation at Syowa-Base (Antarctica). Following Ohm's law, however, the above-mentioned results suggest that the seasonal variation of the ionospheric potential would exist on land.

Notes: Summary Results of measurements of atmospheric electrical potential gradient and conductivity in the free atmosphere using balloon borne radiosondes made at a few stations in India are presented. The potential gradient generally decreases exponentially with height above the exchange layer and the electrical conductivity profiles show corresponding mirror image symmetry. Large variations of electrical potential gradient and conductivity are, however, observed in the troposphere closely associated with clouds, dust and haze and other local meteorological phenomena and space charge effects. Significant though small variations are also observed in the stratosphere, which appear to be associated with the existence of aerosol layers. From an analysis of integrated potential profiles the total atmospheric potential has been calculated and found to have a mean value of 300 kV; the ionospheric potential varies diurnally and seasonally about the mean.

Notes: Summary To study the ionization equilibrium, simultancous measurements of the concentration of small ions (n), concentration of condensation nuclei (Z), and the diffusion coefficient of condensation nuclei (D) have been carried out over the sea. If we take the variation ofD into consideration, the correlation among them was found to be well expressed by the simple formula;q=βn Z. The dependence of the effective attachment coefficient of small ions (β) upon the size of nuclei (2r) were also studied, and β was found to correlate well withD orr. Slight differences of the dependence of β uponD orr over the sea from that over the land seem to be well explained by the difference of charged states of nuclei over the sea and land.

Notes: Summary The nature of negative ions in an air-like gas mixture containing 300 ppm2) of carbon dioxide and 1 ppm of water has been investigated using a drift tube working at atmospheric pressure and interfaced with a quadrupole mass spectrometer. It was found that the most dominant ion under equilibrium conditions is CO4−·(H2O).

Notes: Summary Regular measurements of the dust and nuclei content of the air near the ground at Poona were made during 1967–69 to study the characteristic elements of natural pollution near the ground, its origin and its variation with time, seasons and altitude. The electrical field strength, the positive and negative polar conductivities of the air and the number of positively and negatively charged small ions in the atmosphere near the ground were also measured at the same time. These measurements were repeated at two mountain stations during February, March, and June 1969. The dust content and the electric field show seasonal and diurnal variations opposite to those of the small ion density and electrical conductivity. Thus while the electric field is a maximum in winter, the conductivity and small ion content is a maximum during the monsoon months and the dust content a maximum in the premonsoon summer months. A marked increase in the electric field and the dust and condensation nuclei content is observed since similar measurements were last made in 1935–37 at Poona, with a corresponding decrease in small ion count and conductivity. These large variations are associated with the increased industrialization and urbanization of the regions round Poona during the last thirty years.

Notes: Summary In this paper the quasi-static temperature and stress distributions set up in an elastic sphere by radiation from a point source at a finite distance from the centre of the sphere and out-side it, have been discussed. The temperature boundary condition has been taken in the general form involving an arbitrary function of time. The final solutions have been obtained in terms of series involving Legendre polynomials. Numerical calculations have been done on IBM 1620 Computer and a desk calculator. The results have been represented in graphs.

Notes: Summary The measured data of the atmospheric potential gradientE during aurorae are summarized. It is shown that aurorae in the northern hemisphere decreaseE, and aurorae in the southern hemisphere increaseE. Depending on aurorae intensities, variations ofE reach 30–35% from the mean. Deviations ofE from normal values, on the average, begin 3.5 hours before aurora occurrence and end 3 hours after that.

Notes: Summary We re-examine the problem of the mantle-core discontinuity. By means of theoretical equations of state for silicates in the metallic form, we conclude, once more, that it is a composition discontinuity rather than a phase transition.

Notes: Summary The investigation of the stress-components in an infinite, plate of isotropic homogeneous material with a circular hole has been made by applying Cosserat's theory of couple-stresses. The plate is acted on by two equal concentrated forces at the diametrically opposite points of the inner boundary.

Notes: Summary In low latitude the spatial distribution functions of the source field over the surface and the dimensions of the source, are important in any theory of electromagnetic induction developed for studying the conductivity structure of the Earth. The author has built up a mathematical structure for a theory of electromagnetic induction in anyn-layered earth model in low latitude. No simple solution is assumed for the horizontal distribution function of the source field and no assumption is made about the horizontal gradients of the source. The mathematical structure involves the concept of downward continuity of the field equations inside then-layered earth model. The resulting mathematical functions derived for anyn-layered earth model are complex. Hence a new matrix algebra of complex numbers is introduced by the author and this is built into the theory. From the upward continuity of the field equations, an inequality equation is derived in order to determine the heighth 0 at which the induction field of the earth becomes negligible compared with the source field. The comparison of such heights at two or more stations under the same influence of the source field can be used for the resolution of the lateral distribution of the earch conductivity structure at these stations. The application of the theory will follow in a subsequent paper.

Notes: Résumé Les profils sismiques réalisés en Ligurie confirment l'existence d'un accident crustal important dans la région de Savona. La vitesse apparente voisine de 7 km/s observée vers Imperia entre 10 et 12 km de profondeur pourrait être associée à l'extension possible vers le Sud de l'anomalie d'Ivrea.

Notes: Summary Methods used by Warren and later modified by Niiller and Robinson have been used to investigate the Agulhas Current and other currents associated with it. The results show that with the assistance of a small bottom current of 4 cm/s in the same direction as the main current, the Agulhas Current can proceed round the Cape of Good Hope during three out of four seasons of the year. During the northern winter season, however, the Agulhas Current is so strong that the bottom current may not be able to be so effective and then the Current doubles back near the Agulhas Plateau to form an Agulhas Return Current. There is, however, all the year round an eastward current flowing south of the Agulhas Current but except during the northern winter season, this fed mainly from outside the Agulhas Current area. With a small bottom current of about 2 cms/ the current gets deflected round the Agulhas Plateau to give a meandering effect.

Notes: Summary The study of heat transfer or temperature changes in the surface layers of the soil are important in agricultural science at tropical latitudes. The quantity, thermal diffusivity largely determines the temperature changes produced in the layer of the soil when heat is conducted there from an adjacent layer. Therefore, the authors have determined the thermal diffusivity of the soil at the sites Arapongas (23.5°S, 51.7°W) and São José dos Campos (23.3°S, 45.8°W), in Brazil (South America), in accordance with the simple theory of periodic heat flow in a one dimensional, semiinfinite, homogeneous medium. The diffusivity increases with the increase of moisture content in the surface layers of the soil. The results of diffusivity obtained from these methods agree well with those of past workers obtained by other techniques.

Notes: Summary The equations of motion for the free oscillations of a heterogeneous spherical earth model are derived. It is found that the lateral variations of density and elastic moduli couple the odd(even) harmonics of the spheroidal oscillations with themselves as well as with the even (odd) harmonics of the torsional oscillations.

Notes: Summary An infinite cylinder is assumed to have a small ridge on the surface. The effect of the ridge on the eigenfrequencies of ‘flute’ mode of oscillation is obtained in the linear approximation. The usefulness of these results in seismological problems is indicated.

Notes: Summary In a polluted area, conductivity measurements do not provide significantly better fog forecasts than result from the trend of synoptic reports.

Notes: Summary First motions ofP waves and amplitude spectra ofG 2 andG 3 waves have been used to determine the source mechanism and rupture propagation. The amplitudes ofG 3 waves have been corrected for the attenuation using aQ-model obtained from the amplitude spectra ofG 2 andG 3 waves. Observed directivities for the strike-direction agreed with a model of a bilateral fault propagated primarily from east to west.

Notes: Summary Thermal conductivities at various depths are estimated from the conduction of heat in a freshwater lake during a period of rapid heating leading to the formation of a thermocline. The values obtained can be related to the difference between density at the depth involved and that at the surface.

Notes: Summary The forces due to compressibility of a fluid and their action on moving bodies have been studied. Also a possible practical application of these forces in a propulsion mechanism for vehicles has been discussed.

Notes: Summary After a short description of the soundings carried out during an oceanographical survey in the Sicilian and Sardinian channels in May and June 1970, the results of the nuclei condensation measurements in the sea are here reported. The data presented are the first about condensation nuclei countings in the Mediterranean. The values found are very similar to those ones found by other researchers, during surveys carried out in the Atlantic and Pacific Oceans, even if there is no direct reference to them.

Notes: Summary The author proposes a new technique of magnetic interpretation in the case of a two-dimensional model, whereby six analytical expressions are deduced and computed forDH, DZ, PHB, PZB, AHB andAZB. These expressions denote the induced part of magnetic anomaly inH component, the induced part of anomaly inZ component, the permanent magnetization part ofH anomaly, the permanent magnetization part ofZ anomaly, the sum (DH+PHB), and the sum (DZ+PZB), respectively. The use of a series of these six curves taken together instead of the single profile curve, will improve the existing method of magnetic interpretation, reduce the uncertainties of the inverse problem, and provide a valuable tool for paleomagnetic studies of in situ older rocks commonly found in equatorial Africa. The resulting advantages outweigh the apparent increase in computation. This technique was applied to a field profile obtained across a subsurface dolerite vein, and the results agree with the theoretical predictions outlined.

Notes: Summary Seismicity in the continents is characterized by its foci distribution. Intermediate foci are packed into small spaces with depth range of about 100–200 km. Shallow foci on the other hand, scatter quite widely. Study in the present paper is focussed to the latter feature. A suggestion is given that the wide scattering of shallow earthquakes in the continents as well as the recent remarkable uplifts of mountains are both resulted from the stress in lithosphere plate without entrance (trench) the movement of which is being impeded.

Notes: Summary Transient electromagnetic response of a cylindrical conductor covered by (a) an insulated and (b) a galvanically connected coaxial shell has been obtained. The exciting pulse is produced by switching off a long alternating current source. The study incorporates the influence of magnetic permeability contrast of the cylinder with the surrounding medium and also that of the inhomogeneity in the conductivity. The generalised initial value problem is significant in the study of certain geomagnetic anomalies. The results will also aid to the interpretation of induction prospecting data for elongated porphyry conducting mineral deposits.

Notes: Résumé On définit le modèle stochastique des séismes dans la région de Vrancea et on établit en même temps une relation magnitude-fréquence correspondent à la répartition lognormale des magnitudes. On donne des formules pratiques de calcul des coefficients de la relation magnitude-fréquence et sont définis certains termes de séismicité. On donne enfin la définition des caractéristiques informationnelles du phénomène séismique, l'entropie et l'énergie informationnelle et on calcule ces caractéristiques pour des répartitions exponentielles et lognormales des magnitudes.

Notes: Summary Dispersion in Rayleigh waves is discussed for semi-infinite media withμ =μ 1(1 ±ε cos s z) andμ =μ 1(1 ±ε cosh s z), μ being the rigidity of the medium. A few workers tried with the above Fourier type of model but failed to find the dispersive nature. Because they neglected εs due to the complexity of the calculation they arrived at a non dispersive frequency equation. This difficulty is removed in this paper and a dispersive frequency equation is obtained which shows both direct and inverse dispersion. The second model leads to non-convergent solution forz→∞ but shows many interesting results which are also discussed.

Notes: Summary This paper is concerned with the determination of torsional vibration of an orthotropic Cylindrical Shell assuming the elastic constants to be proportional to thenth power of the distance from the axis of the shell. The solution is obtained in terms of Bessel functions.

Notes: Summary The field dependence of magnetic remanence in laboratory deposited sediments is re-examined in terms of the average orientation of small grains of magnetite subject to the combined effect of an aligning field and thermal agitation. The classical (Langevin) formula for paramagnetic susceptibility is generalized to describe an assembly of grains with magnetic moments having a uniform distribution of values between zero and an upper limit, yielding a simple analytical expression in excellent accord with the pioneering measurements of Johnson, Murphy and Torreson. Comparison of theory and observation shows that the grain moments are intermediate between the values expected for single domains and multidomains, confirming the existence of pseudo-single domain effects, as deduced from observations of thermoremanence.

Notes: Summary Results of sunspot cycle influence on solar and lunar ranges at a low latitude station, Alibag, outside the equatorial electrojet belt, show that the sunspot cycle association in solar ranges is three times that of the lunar ranges in thed- andj-seasons. This is in general agreement with the earlier results for non-polar latitude stations. The association with sunspot number of individual lunar amplitudes is greatest for lunar semidiurnal harmonic in thej-season. During this season, the sunspot cycle influence on lunar variations is more than that on solar variations, thereby indicating that the lunar current is situated at a level more favourable for sunspot cycle influence than the level of the current associated with solar variations. With the increase in solar activity a shift appears in the times of maxima of semidiurnal lunar variation towards a later lunar hour ine- andj-seasons and in the year.

Notes: Summary In this paper some measurements of the resistivity of Talchir and Barakar sandstones of the Jharia Coal field under dry and saturated conditions have been made and the results are discussed in the light of known theories. Techniques of measurement have been briefly described.

Notes: Summary The generation of very high atmospheric potentials is ascribed to the sudden separation of a cloud, or portion of it, into an upper and lower section, substantially, of opposite polarities. Said abrupt cut being, the mechanical effect produced by local wind gusts. The related mathematical analysis shows how “theoretically infinite” voltage spikes may be generated as forced electrical transients when a cloud separates into two sections.

Notes: Summary For a periode of five months, the chloride particle concentrations in the air near the ground were measured at the west-coast of Denmark. The results show clearly, that high concentrations are connected with west wind, especially with passages of cyclones over Denmark or Skagerrak, low concentrations with east wind and anticyclones over Scandinavia. This lead us to the conclusion, that high concentrations of chloride particles are generated in the storm-areas of deep cyclones over the sea.

Notes: Summary Three dimensional magneto-elastic equations pertaining to the problem of propagation of axial Rayleigh waves on the surface of elastic cylinder of isotropic material have been solved. Two cases have been considered — first, when the density varies linearly and second, when it varies inversely as the radius vector and frequency equations for both the cases have been obtained.

Notes: Summary P n velocities determined from seismic refraction measurements, show significant differences between Southern Finland (7.96 km/sec) and Southeastern Norway (8.20 km/sec). TheP n/Sn velocity ratios (k) were determined from earthquake and explosion data, and the observed variation ofk indicates lateral variations in theP n and/orS n velocities in Fennoscandia.

Notes: Summary Rotatory vibrations of a thick spherical shell of isotropic non-homogeneous material with rigidity μ and density ϱ given by (i)μ =μ 0 r -2 withQ =Q 0 r -2 e 2mr and (ii)μ =μ 0 r m withμ =Q 0 r n have been discussed and the frequency equation is derived with numerical enumeration of frequency in each case.

Notes: Summary The equations of mechanical motion and electromagnetic equations of Maxwell have been used to investigate the disturbances in a viscoelastic rod of Reiss type placed in a magnetic field.

Notes: Summary Steady Couette flow ofNoll's simple fluid between two porous plates has been considered. It is seen that such flow, though not strictly lineal, is viscometric and unique solution for the main flow exists, in general, under Lipschitz's condition on the shearing function. Special cases have been discussed.

Notes: Summary Electromagnetic response characteristics of an inhomogeneous permeable cylinder surrounded by a thin insulated concentric dissipative shell is obtained in presence of a line-source of current. The 3-layer boundary value problem is solved by assuming the thickness of the shell to be much smaller than the skin-depth in the shell. Numerically computed results are presented in the form of argand diagrams to examine the influence of the shell parameters (conductivity and its proximity with the core) and magnetic contrast. The multi-frequency response of the system is also given which resolves the two conducting layers and analyzes the frequency dependence of screening behavior of the shell.

Notes: Summary A comparison of field variation with depth for CFS and DFS inside a homogeneous earth of different conductivity has been utilized to study the relative performances of these two methods. It is found that CFS shows a uniform and smooth variation of field over the entire conductivity range while DFS maintains such a uniformity in a limited range only. Resolution is seen to be more for the lower values of the conductivity parameter in case of CFS and for higher values in case of DFS.

Notes: Summary 1. During early embryogenesis (from morula to late tail-bud) of Triturus vulgaris the DNA content of isolated nuclei from various regions was measured cytophotometrically. The measurement data (50 to 70 for each region and developmental stage) were collated to so-called karyograms, which show the DNA doubling during interphase and serve for determining the “normal” DNA content (DNA value of G1-nuclei). 2. Thereby it became evident that the DNA content of G1-nuclei is not constant in the course of development, but varies with stage and region specifically. Beginning with high values, DNA decreases from morula to early gastrula. In the neuroectoderm (region 2), chordamesoderm (region 1), and endoderm (region 4) remarkable DNA increases of short duration occur at one time in the mid to late gastrula and at another time in the late neurula. By contrast in the presumptive epidermis an increase of DNA has only been detected during gastrulation. 3. With regard to the extent and rate of changes in DNA content there are good agreements on the one hand and considerable differences between various regions on the other. 4. In explantation experiments these results (with the exception of endoderm) could be confirmed for isolated material too. Thus non-induced ectoderm of the gastrula shows just the first DNA increase, but induced ectoderm shows also the second one. In isolated presumptive chordamesoderm both phases of DNA increase are visible, whereas isolated endoderm is characterized by absolute constancy of DNA. 5. In isolated ectoderm Actinomycin D (1 and 2 Μg/ml) prevents the additional DNA synthesis during gastrulation, whereas the second DNA increase is not impaired. (Actinomycin D does not interfere with the normal DNA reduplication.) 6. Puromycin (20 Μ/ml) has no influence on the DNA increase in the course of gastrulation and neurulation. 7. The temporal correlation of both phases of additional DNA synthesis with well-known embryological, cytological, and biochemical changes in the embryo leads to the assumption that the phase-specific increase of DNA is an expression of enhanced gene activity in definite regions of the embryo. The possibility of partial amplification of genes for the purpose of increase of transcription capacity is discussed, and a parallel is drawn with the multiplication of the nucleolus organizer during the maturation of oocytes.

Notes: Summary Xenoplastic recombinations of animal and vegetative parts ofAmbystoma mexicanum and Triturus alpestris blastulae, and similar recombinations of parts of3H-thymidinelabelled and unlabelledAmbystoma mexicanum blastulae demonstrate convincingly that the vegetative part (zone IV, see Nieuwkoop, 1969a) of such a recombinate does not contribute to mesoderm formation, but exclusively forms endodermal derivatives. In contrast, the animal cap of the blastula (zones I.II)—which only gives rise to atypical ectoderm if isolated—not only furnishesall the ecto-neurodermal derivatives, butall the mesodermal structures of the developing recombinate as well, and finally to a varying extent forms additional endodermal structures in the recombinate. In the recombinates endodermization of the ectodermal cap occurred at the anterior end of the invaginated archenteron—corresponding to the presumptive pharyngeal endoderm —, and along the dorsal side of the endodermal tube, while an endoderm-like epithelium is formed at the boundary between the caudal endoderm and the ectoderm (proctodaeum formation). These results suggest that in normal development also endodermization occurs in the “ectodermal half” of the egg. This occurs particularly on the dorsal side, leading to the formation of the presumptive pharyngeal endoderm situated above the dorsal blastoporal groove. These experiments show that the vegetative “half” of the amphibian blastula is firmly determined as the future endoderm, whereas the animal “half” is still virtually undetermined and pluripotent.

Notes: Summary The differentiation of abdominal imaginal discs of matureCalliphora erythrocephala larvae has been studied by thermocautery and extirpation of the discs, and by implanting them into larval hosts of the same age. The experiments give information on (a) the morphology of the imaginal abdomen, and (b) the “regulative activitybetween imaginal discs”. 1. Within each of the first to seventh larval abdominal segments, we identified two pairs ofabdominal discs, a dorsal and a ventral one (Fig. 6). Besides, the terminal part of the abdomen holds the paired lateral genital discs and the unpaired (median) genital disc, which are of different shape in both sexes (Fig. 9, 10). 2. The imaginal discs of a specific larval segment differentiate only into the integument of the corresponding imaginal segment. The dorsal pair of discs gives rise to the dorsal region (≈tergum, dorsum), the ventral pair to the ventral region of the imaginal segment (≈sternum); the left and the right discs of a larval segment develop into the corresponding halves of the segment in the adult. 3. Thelateral genital discs constitute the imaginal discs of the eighth segment, while thegenital disc includes the imaginal cells of the fused segments 9–11 (Fig. 30). 4. Our experimental results confirm thenumbering of segments in the imaginal abdomen, as proposed by Graham-Smith (1938), Crampton (1942), Hennig (1958), and Salzer (1968). 5. The large tergites of the imaginalpreabdomen consist of an area dorsal to the spiracles, arising from the dorsal abdominal discs, and of parts lying ventral to the spiracles. These ventral parts of the tergite as well as the “pleural membranes” and the sternite originate from the ventral discs (Fig. 31). 6. The small first dorsal plate of themale postabdomen proves to betergite 6. The sclerite, bordering the genital pouch ventrally, belongs to two segments; it should be termedsternite 6+7. The large sclerite, called syntergum 7+8 by Salzer (1968), is formed by several pairs of discs: the left ventral abdominal disc 6, the dorsal and ventral discs 7, and the lateral genital discs (Fig. 31). Thus, we term it thetergosternite 7+8. 7. In the male only the last segments of the postabdomen participate in therotation during metamorphosis: The eighth segment is rotated through 180° (=inversion); the hypopygium (=segments 9–11) is circumverted, i.e. twisted through 360° (Fig. 31). Thus,Calliphora has no “postabdomen circumversum” as Salzer (1968) assumed, but merely a “hypopygium circumversum”. 8. Our results (Fig. 32) support the current morphological interpretation of thefemale postabdomen or ovipositor, as proposed by Crampton (1942) and Hennig (1958). 9. Theinternal genitalia of the male (without testes) originate from the genital disc. On the contrary, the female internal genitalia (without ovaries) develop from the lateral genital discs (oviduct, uterus, vagina, spermathecae) and the genital disc (parovaria). A comparison of the developmental capacities of theDrosophila genital disc with those of the lateral and median genital discs ofCalliphora shows that in the female ofDrosophila the equivalents of the lateral genital discs have been incorporated into the genital disc (Fig. 30). 10. Afterelimination of any one of the abdominal or lateral genital discs from the mature larva, the complementary disc of the opposite side gives rise to more than accords to its prospective significance (but see the results of Zalokar, 1943, and Murphy, 1967, on cephalic and thoracic discs inDrosophila). Our data on lateral genital discs do not support the view that the reported increased differentiation is due to a “regulation between discs of a single bicentric field” (Pantelouris and Waddington, 1955). Our data may be explained more easily if we assume the existence of an inhibitory effectin situ between the discs of one pair, which is abolished after elimination of the partner (cf. chapter 6.3.).

Notes: Summary 1. The gametogenesis ofHydra attenuata undHydra circumcincta has been examined by light- and electron-microscopical methods. 2. In most cases one cell of each group of oogonia II develops into an oocyte, which engulfs the neighbouring oogonia II by phagocytosis. The oocytes fuse to form a polyenergetic plasmodium, in which one of the nuclei becomes the germinal vesicle, while the others degenerate. The ooplasm contains a great number of necrotic cells, so called “shrunkencells”, which we suggest participate to some extent in the formation of the ooplasm. 3. Once the egg has reached the spherical form, it is fertile for only 7 hours. 4. During spermatogenesis cell division may not occur in one or both reduction divisions, so that 2 or 4 spermatozoa are differentiated within a common membrane. The spermatozoa ofHydra attenuata are of primitive structure without acrosomes. 5. The ejaculation of the mature spermatozoa occurs in clusters at different time intervals. 6. Under optimum conditions (9–12° C; pH 7.3) the viability of the spermatozoa is about 4 1/2 hours. 7. Fertilization is favoured by the following factors: synchronisation of the male and female sexual periods, longer duration of the male sexual period, ejaculation of the spermatozoa in clusters, short spaces between the sexual partners in a population.

Notes: Summary 1. Medusae buds ofPodocoryne carnea up to the stage 8–9 (see Frey, 1968 for description of stages) are able to dedifferentiate and form stolos and polyps. Isolated buds of stages 9 and 10 always develop to medusae. 2. Repeated traumatisation of the isolated buds greatly increases the rate of dedifferentiation of the stages 1–8. 3. The rate of dedifferentiation is clone-specific. 4. In the critical stage 8–9, after which no dedifferentiation is possible, the structural differentiation of medusae-cells is completed and there is little mitotic activity. 5. The loss of capability for dedifferentiation is correlated with the swelling of the outer mesoglea. 6. Cell-aggregates of dissociated buds behave morphogenetically similar to isolated intact medusae-buds. 7. Medusae fragments of the umbrella, which are free of interstitial cells, transform in a process of metaplasia into stolos and polyps. 8. Dedifferentiation starts with the subumbrellar muscular system and later involves the subumbrellar sheet with the radial canals. The discussion of the transformation of musclecells into entoderm-cells is based on electron-optical investigations.

Notes: Summary Imaginal discs ofDrosophila melanogaster larvae, 24–53 hrs after oviposition, were transplanted into mature immobile larval hosts. The transplants did not respond to the hormonal stimuli of metamorphosis, but instead completed their larval development. When reinjected into mature larval hosts, they now differentiated the full set of their presumptive imaginal structures. The process of acquiring competence for metamorphosis appears to be independent of the hormonal conditions.

Notes: Summary The synthesis of protein and lipid was studied in the testis and thoracic tissues ofDrosophila hydei by radioisotope incorporation. The formation and accumulation of late stage gametes in the testes during maturation was accompanied by more than 4-fold increases in both lipid and protein synthesis rates. Though there was an 8-fold increase in the rate of protein synthesis during thoracic tissue maturation, the rate of lipid synthesis little more than doubled. By comparison the rates of protein synthesis were high in mature testis and thoracic tissues, whereas the rate of lipid synthesis was high in the mature testis but low in both immature and mature thoracic tissues. Label incorporation from pyruvate and L-alanine into protein in thoracic tissue appeared to be highly dependent on Krebs cycle activity, whereas pyruvate and L-alanine label incorporation into protein in the testis was primarily from L-alanine and its derivatives. Both pyruvate and L-alanine were decarboxylated prior to label incorporation into lipid in the testis and thoracic tissue.

Notes: Summary The development of the oocyte takes place in four classical phases: premeiosis, previtellogenesis, vitellogenesis and maturation. During previtellogenesis, nucleus and cytoplasm grow considerably. The nucleolar material breaks up into numerous masses and laminae and nuclear extrusions are very frequent. The number of ribosomes and mitochondria increases markedly; the mitochondria show pronounced morphological modifications: stacking, honeycomb-like figures. Lysosomal formations are numerous. During vitellogenesis, the nucleus shows little activity and yolk accumulates in the cytoplasm. The number of ribosomes and mitochondria decreases. During maturation, the Golgi apparatus seems to bud off vacuoles in the cortical cytoplasm. Cytological and cytochemical modifications are discussed in relation to the physiological development of the oocyte.

Notes: Summary The aim of the present study was to investigate the development of enzymes in the chick pancreas and to study the influence of a heterologous mesenchyme (lung mesenchyme) on the differentiation of these enzymes. 1. The normal development of chymotrypsin, carboxypeptidase A, amylase, and lipase in the chick pancreas has been studied. The proteolytic activities as well as the amylase become detectable between day 14 and day 17. The total and specific activities of these enzymes remain rather low during about a week, and they show a spectacular rise just before hatching. In contrast to the proteolytic and amylolytic enzymes, lipase could not be detected before day 20 and showed a rapid increase just before and during hatching. 2. These enzymes have also been studied in the spleen and in the lung. Both organs show low and constant activities of chymotrypsin, carboxypeptidase A, and amylase. They are devoid of lipase. The latter enzyme appears to be strictly specific for the pancreas. 3. The specific activities of the various enzymes were measured in the various lobes of the pancreas; however, no significant differences were found. 4. All enzymatic activities were found in the organs obtained from an association of pancreatic epithelium with pulmonary mesenchyme and which developed in coelomic grafts. These activities were as high as in control organs where the pancreatic epithelium was not dissociated from its own mesenchyme. In conclusion it was found that the determined pancreatic epithelium, if it is associated with a pulmonary mesenchyme at the early embryonic stage, gives rise to biochemically normal exocrine pancreatic tissue.

Notes: Summary Unilateral removal of ectoderm and subjacent mesoderm practised onPleurodeles waltlii, at different stages of the neurula and tailbud embryo, causes a more or less important reduction of larval gonocytes on the operated side. It has thus been possible to locate the germ cells at the stage of the young neurula (st. 15) in the neighbourhood of the blastopore. Between stages 21 and 22, these cells begin a dorsal migration along the pronephric duct. The absence or reduction of the number of gonocytes, as a consequence of the extirpation of an ecto-mesodermal area, leads us to think that the germ cells are located in the mesoderm and that their removal cannot be compensated by presumptive somatic cells.

Notes: Summary Experiments were performed on 2- to 2 1/2-day chick embryos in order to study the role of the neural tube in the development of the dorsal plumage. Pieces of neural tube were excised or replaced by various living or inanimate implants. In other experiments, a screen was interposed between neural tube and somitic mesoderm. The excision resulted in the non-differentiation of a portion of the spinal pteryla: absence of several feather chevrons without disruption of the hexagonal feather pattern, or formation of an apterium or an irregularly feathered area. The replacement by a piece of agar or tantalum or by another tissue (gut, somatopleural mesoderm, somites) led to the same type of dorsal plumage deficiencies as those which were produced by the excisions. Similarly, the replacement by a fragment of neural tube treated at 100° C severely interfered with the development of dorsal plumage. On the contrary, when the neural tube had been exposed to a temperature of 60° C only, the spinal feather pattern was normal or nearly so. The interposition of a solid screen 0.8 to 2 mm in length (tantalum, egg shell membrane, Millipore filter) between neural tube and somitic mesoderm resulted in the formation of a featherless triangular notch in one side of the spinal pteryla. The screen prevented the development of the feathers in the feather field lateral to the screen. These experiments show that the neural tube is indispensable for the differentiation of the dorsal feather pattern. The neural tube cannot be replaced by inanimate objects or by any of the tested tissues, not even by feather-forming ones like somites. Its presence is likely to be necessary for the transformation of dermatomes into predermal cells. When it is absent, dense feather-forming dermis does not form at that level and, consequently, the corresponding portion of the spinal pteryla cannot develop.

Notes: Summary Isolated Amphibian gastrula ectoderm, pretreated in different ways, was combined with endoderm. 1. Untreated ectoderm separates from endoderm after several days. 2. Ectoderm, treated with the vegetalizing inducing factor, is surrounded by endoderm, which spreads over the treated ectoderm as an uni- or multicellular layer. 3. Treatment of ectoderm with actidion (2 Μg/ml for 5 h or 1 Μg/ml for 20 h), an inhibitor of protein synthesis, prior to induction prevents the spreading of endoderm over ectoderm. 4. Treatment of ectoderm with AcD, an inhibitor of RNA synthesis, prior to induction does not prevent the spreading of endoderm over ectoderm. 5. Treatment of ectoderm with AcD without inductor changes the affinity of ectoderm to endoderm. Ectoderm, treated with 1 Μg/ml AcD, spreads over the endoderm as a thin layer. After treatment with 2 Μg/ml AcD, in some cases endoderm spreads over the ectoderm.

Notes: Summary 1. In the chick limb bud, histochemical Cholinesterase (ChE) activity has been studied from stage 13 of Hamburger and Hamilton to stage 29 (6 days). 2. In stage 13 the neural crest cells on their intraectodermal migration into the limb field are revealed by the ChE reaction (Fig. 1). 3. In stage 14–16 the ectoderm of the lateral body wall covering the Wolffian ridge exhibits ChE activity (Fig. 2). 4. In the following stage the apical ectodermal ridge is formed from this positive ectoderm. Between the wing and leg bud ChE activity disappears. So, in the early limb bud ChE activity is confined to the apical ectodermal ridge and the ectoderm. The mesodermal core is negative (Fig. 3). 5. From stage 20 onwards ChE activity becomes demonstrable in the preaxial mesoderm, too. The activity is accompanied by a loosening and vascularisation of the tissue (Fig. 4–6). With further development it spreads distally. In the distal region the asymmetrical ChE distribution within the mesoderm (positive preaxially and negative postaxially) is maintained until stage 27. 6. In stage 25 the mesodermal ChE activity reaches the distal tip of the wing. Concommitantly, activity disappears from the apical ectodermal ridge (Fig. 8). 7. As cartilage condensations are formed in the loosened central mesoderm, ChE activity increases further in the condensing cells. Finally it disappears from the differentiated cartilage (Figs. 7–10). 8. In the presumptive soft tissue ChE activity disappears temporarily. After the cartilage condensation has formed centrally myoblasts with high activity develop in the peripheral tissue (Figs. 8–10). 9. The invading nerve fibers also exhibit a high ChE activity. They make their way in the negative zone between cartilage and muscle (Figs. 8–10). 10. Like in the development of other organs, ChE activity in the chick limb bud is correlated to morphogenetic changes of the reacting cells. Concommitantly, ChE activity is the first indication of the onset of organ formation and cytodifferentiation.

Notes: Summary In an earlier paper (Hauser, 1969) it was suggested that the subcommissural organ (SCO) in the roof of the diencephalon might control normal straight regeneration after amputation of the tail tip inXenopus larvae, by means of Reissner's fibre (RF) its secretory product in the central canal of the spinal cord. This hypothesis has been experimentally tested, with results that appear to confirm it, as follows: 1. Elective destruction of the SCO caused characteristically disturbed tail regeneration, while other brain lesions did not affect normal tail regeneration. 2. RF degenerated within 24 hrs in the caudal neural tube after it had been severed at the base of the tail. In most cases the separated parts of the neural tube resumed contact within less than 4 days in such a way as to allow RF re-entry into the central canal of the caudal piece, but occasionally reconstitution of RF was prevented by complete or partial obstruction of the central canal. Histological examination revealed that whether or not the tail regenerated normally depended entirely upon the reconstitution of RF, and not on the restoration of central canal continuity as such. The implications of these results, and of similar results recently obtained by Rühle (1971), for the understanding of SCO function are discussed.

Notes: Summary The salivary glands ofDrosophila melanogaster have been examined by electron microscopy for fine structural alterations occurring during larval and prepupal stages. The changes observed in the glands have been correlated with the puffing patterns of the polytene chromosomes at corresponding stages. In early third instar larvae, the lumen of the salivary gland appears empty, and no signs of secretory activity are visible in the glandular cytoplasm. From puff stages 1 to 6 the endoplasmic reticulum becomes reorganized and increases in volume. Electron dense material appears within its cisternae and subsequently within the Golgi saccules. Dense secretory granules then appear to be elaborated from the Golgi by terminal budding; these granules represent the ‘glue’ for adhering the pupa to its substrate, and gradually increase in size and complexity. By puff stage 6 their contents have been liberated into the glandular lumen. Following puparium formation, those granules which are not extruded coalesce to form larger granules. Other dense bodies and autophagic vacuoles, considered to be lysosomes, appear, and the ‘surplus’ secretory granules begin to display myelination at their peripheries; ultimately they are reduced to dense residual bodies. At puparium formation, the lumen is depleted of the glue and contains flocculent material. Histolysis commences after puff stage 11, and the cytoplasm becomes vacuolated and opaque; the nucleus becomes reduced in volume and crenated in outline. Nuclear blebbing occurs after puff stage 12, and material seemingly moves from the nucleus into the cytoplasm; the glandular lumen now becomes empty. An attempt has been made to ascertain how the chromosomal puffing activity relates to these cytoplasmic developments.

Notes: Summary The planulae ofHydractinia, the metamorphosis of which normally is induced by certain bacteria, will undergo transformation into polyps also when exposed to a lithiumpulse. The optimal concentration and incubation period for rapid and complete transformation have been determined at 24 mM Li+ and 2 hrs respectively. 96 mM K+ applied for 2 hrs will also result in some induction. The possible mode of action exerted by the Li-ion as compared with induction caused by bacteria is discussed.

Notes: Summary 1. The fine structure of the „germinal cytoplasm“ of the dividing egg ofXenopus laevis has been studied. Mitochondria which occur in great numbers and electron-dense bodies associated with them are the two characteristic components of the so-called “germinal cytoplasm”. 2. The electron-dense bodies are composed of granular and fibrillar elements and often contain an internal light area. Long fibrillar elements have been found within the light area. The organization of the electron-dense bodies is strongly reminiscent of that of the polar granules inDrosophila.

Notes: Summary A comparison of equal amounts of labeled nuclear RNA of dorsal ectodermmesoderm and endoderm cells of frog neurulae by DNA-RNA hybridizations revealed more kinds of DNA-like RNA in the ectoderm-mesoderm nuclei.

Notes: Summary 1) 3H-Uridine incorporation into the RNA of eggs ofMusca domestica was measured by means of autoradiography. In addition, protein synthesis was studied by measuring incorporation of3H-amino acids. 2) The onset of embryonic RNA synthesis was found to occur after the 10. division of the cleavage nuclei. 3) Protein synthesis occurs in mature oocytes as well as in freshly laid eggs. The rate of synthesis in fertilized eggs begins to increase when the cleavage nuclei penetrate the periplasma. At the end of blastodermal development, the rate of protein synthesis reaches a value which remains constant until differentiation of the germ layers. Immediately after deposition of the eggs, the rate of incorporation of3H-amino acids is higher in unfertilized eggs than in fertilized ones. 4) At oviposition the radioactivity is uniformly distributed over the whole egg. During further development more radioactivity is accumulated in the periplasm than in the inner part of the egg. Already before penetration of the cleavage nuclei, a higher rate of protein synthesis is observed in the posterior pole-plasm than in any other part of the periplasm. 5) Immediately before the beginning of organogenesis, a region specific incorporation of3H-amino acids into nuclei can be observed. 6) The rÔle of the maternal RNA in protein synthesis in the developing egg as well as its rÔle in the determination of certain egg regions (especially of the posterior pole-plasm) is discussed. The beginning of RNA synthesis and the simultaneous increase in the rate of protein synthesis are interpreted as processes of embryonic differentiation. It is assumed that the maternal RNA stored in the pole-plasm has a determinative function.

Notes: Summary Head blastemas in regeneratingDugesia tigrina (Planaria) have been studied light microscopically and electron microscopically. Acid phosphatase activity has been followed in early blastemas using a light microscopical cytochemical method. The possibilities of a collagen synthesis inhibiting substance α-α′-dipyridyl in analyzing fibrillogenesis in planarians have been explored. Following a brief discussion of the neoblast concept the general organization and characteristics of the blastema are described. Regeneration of the muscle-connective tissue filament system including the subepidermal membrane is analyzed in detail. It is stressed that the muscle cells, the filamentous sheaths and the subepidermal membrane in planarians should be visualized as a mutually dependent, integrated system. The hypothesis is proposed that neoblasts differentiate into myoblasts which both synthesize myofilaments and collagen. Collagen forms the filaments of the subepidermal membrane-muscle sheath system. No certain interference with collagen synthesis and secretion could be demonstrated in the experiments involving α-α′-dipyridyl. There was no evidence for significant changes in the activity and pattern of acid phosphatase during early stages of regeneration. The problems concerning the existence of neoblasts, their participation in regeneration and their origin (stock cell or result of a dedifferentiation process) are discussed.

Notes: Summary 1. Gynandromorphs were recovered fromIn(1) X c2,w vC/y Hw f 36a females. The distribution and frequency of the adult male and female areas indicate a very early loss of theIn(1) X c2,w vC chromosome. An analysis of mosaicism of the dorsal thoracic structures was carried out in order to derive a morphogenetic map of the location of their presumptive cells. It was constructed using 12 landmarks in the notum, 16 in the wing surface, the humerus and the haltere. 2. By several methods, the minimal number of cells populating the dorsal mesothoracic anlage was estimated to be about 40. 3. A map of the distances in trichomes—adult cells—between landmarks in the notum and the wing is presented. A comparison of the morphogenetic map and the adult map shows regional differences in growth. Whereas in the notum growth is isodiametrical, in the wing growth is preferentially along the proximo-distal axis of the anlage. However, the calculated mean mitotic rate is the same in both wing and notum. 4. Mosaicism in the notum is undetermined with respect to the adult structures. In the wing a virtual line along vein IV separates two wing regions, anterior and posterior, with different morphogenetic characteristics. 5. Possible morphogenetic mechanisms controlling the mesothoracic disc development are discussed.

Notes: Summary Hydra oligactis exposed to 3 μg/ml actinomycin D for 24 hours regenerated only the first pair of tentacles (the mid-laterals). If left uncut, actinomycin D treated animals underwent a reduction of the normal number of tentacles to two or less. Inductive activity was retained in the 2-tentacled hypostomes. However, the tentacles present exhibited reduced capacities to capture and manipulate prey. Histological studies showed that the tentacles of actinomycin D treated hydra were morphologically identical to those of the controls. The interstitial cell (I-cell) population of the treated animals, however, became depleted. Replacing the hypostome of an actinomycin D treated hydra with a normal hypostome reversed the cellular effects of actinomycin D treatment. The modifications in tentacle morphogenesis occurring after actinomycin D treatment are consistent with an impairment of hypostomal function in the animal. It is suggested that the morphological site of this malfunction may be in the nervous system.

Notes: Summary Larvae ofTriturus alpestris (stages according to Glaesner: 27, 34, 39 and 43) were kept for 24 hours in a solution containing 10−4 gr Triethylenmelamin (TEM) per ml tap water. Thereafter, they were further grown in pure tap water. Light microscopically, a fading of mitotic figures and an enlargement of cells prepared to divide were observed within the retina. Pyknotic nuclei and cell death occured in the zones of cell differentiation. The various developmental stages were differently affected by TEM. Electron microscopically, alterations of retinal cell nuclei were found to occur as early as 12 h after the onset of TEM- incubation. Fragments of nuclei which otherwise appeared morphologically normal were observed to develop by an invagination of the nuclear membrane and a subsequent fusion of the small vesicles which originated from the nuclear envelope. These fragments became completely digested. The fragmentation process eventually involved the entire nucleus and resulted in cell death. In peripheral zones of the retina, cells became enlarged, their nuclei being lobulated and their chromatin becoming transposed towards the periphery. Autolytic processes were observed to start in particular areas of the cytoplasm and to extend all over entire cells. In TEM-treated eyes, the pigment epithelium became grossly hypertrophied. This epithelium impressed by elongated and round melanosomes and a surprisingly large number of premelanosomes. The mechanism of TEM-effect was compared to that of other alkylating cytostatic drugs and discussed in connection with the observed cytological alterations.

Notes: Summary 1. UV-irradiation, of the entire ectoplasm during intravitelline cleavage stages causes the formation of a pseudoblastoderm. The damaged superficial areas remain free of cleavage nuclei, which contact with their cytoplasm and form a blastodermlike layer inside the yolk-entoplasm. However there is no visible differentiation in the pseudoblastoderm before its death. 2. Disc-electrophoresis was performed on normal developing eggs and on those in pseudoblastoderm stages in order to find out whether the protein pattern of the egg is affected by the loss of cortical regions. Normally with blastoderm formation 2 new protein fractions occur in the electrophoretic pattern. But in the pseudoblastoderm egg they are absent. Three other fractions, which will be removed in the normal blastoderm egg were also not detected in the pattern of the pseudoblastoderm egg. One protein fraction synthetized during intravitelline cleavage and always present in later development could not be observed in pseudoblastoderm stages. 3. Micro-disc-electrophoresis of isolated yolk-entoplasm material was carried out to locate certain protein fractions in the egg system. The same protein fraction, which could be damaged by UV-treatment of the ectoplasm is not detectable in the electrophoretic pattern of the underlying yolk-entoplasm. Therefore this fraction must be situated in superficial regions of the egg confirming reported results of autoradiographic investigations. 4. This leads to the conclusions, that the synthesis of certain protein fractions depends on the functional condition of cortical egg components. Other physiological processes, which are not affected by the loss of the periplasm take place without influence of superficial regions. Beside their role as egg areas in which physiological ooplasmatic factors are located the superficial egg components contain special protein structures.

Notes: Summary 1. This study deals with the postembryonic development of the male genital armature inLymantria dispar. 2. The Herold's organ, a ventro-median, sak-shaped, epidermal invagination of the 9th abdominal segment, is already present in the newly hatched larva. It is linked to the testes by two mesodermic strands (the future vasa deferentia). 3. In the 3rd stage larva (total number of stages: 7) the lateral walls of the proximal part of the Herold's organ starts to develop primary lobes. 4. Beginning with the 7th day of the last larval stage, the primary lobes are subdivided into two pairs of secondary lobes. The proximal lobes represent the “Anlagen” of the aedoeagus and the ductus ejaculatorius, the distal lobes represent the “Anlagen” of the valvae. 5. Before the onset of the pupal phase (9th day of the last larval stage), the fuson of both aedoeagus-lobes gives rise to the unpaired aedoeagus-“Anlage”. During the prepupal phase the valvae-lobes are translocated to the body surface. 6. Beginning with the 2nd day of the pupal phase the valvae-“Anlagen” grow rapidly and differentiate into the valvae-basis and the valvae-hook. Abdominal segments No. 9 and No. 10 undergo reduction and are drawn into the segment No. 8. The aedoeagus-“Anlage” appears at the body surface; the anellus is formed. 7. The chitin ring develops from the pleurals and from the tergum of the 9th abdominal segment. The saccus is formed by invagination of the epidermis at the borderline between the segments No. 8 and 9. The uncus derives from paired “Anlagen”, which are recognizable lateral of the anal groove in the 3 days old pupa. They develop during the reduction of the pupal cone and the outgrowing of the anal cone and fuse to the unpaired uncus. 8. At the 9th day of the pupal phase, the morphogenesis of the genital armature is completed and is followed by the histogenesis.

Notes: Summary 1. In the first part of the paper the potentiality of autonomous differentiation in the Herold's organ ofLymantria dispar is investigated. a) The development of the implanted Herold's organ is observed in a host; after molting of the imago, the implanted genitale is removed from the body cavity and analyzed. Aedoeagus and anellus are quite normally formed. Two lateral, inverted chitin vesicles are found to be identical with the valvae. All differentiations observed within the complex are homologous with parts derived from the Herold's organ. b) Transplantation experiments show the necessity of the exact position (9th abdominal segment, ventromedian) for the evagination and typical differentiation of the valvae-“Anlagen”. This means that the epithelial translocations at the posterior end of the larva during the metamorphosis are essentially engaged in the displacement of the valvae-lobes to the body surface and for their normal development. 2. In the second part of the paper regulation capacity and state of determination of the Herold's organ in the last larval stage is examined. a) Partial and even complete duplication of the aedoeagus is observed after halving the Herold's organ but leaving the epidermal connections of both halves. If—after halving the Herold's organ—the epidermal connection of one half only is removed, both halves show separately the formation of complete genitale. The halfwith epidermal connection is able to develop as an intact Herold's organ, the halfwithout epidermal connection is able to develop as one whole Herold's organ after implantation. In some of the cases regeneration of the removed part does—for unknown reasons—not occur. b) After implantation of a dissected Herold's organ, three classes of results are observed: I. both halves form separately a regenerated, complete genitale, II. only one half regenerates, III. none of the halves regenerate. The regeneration of the removed part occurs during the last larval stage before the onset of the prepupal phase. c) The state of determination of the Herold's organ after subdivision of the primary lobes into the aedoeagus-lobe and the valvae-lobe is analyzed by means of implantation of portions of the Herold's organ. Aedoeagus- and valvae-lobes are irreversibly determined according to their position in the “Anlagenfeld”. Regulatory processes are possible only within consistent parts of the “Anlagenfeld”.

Notes: Summary The soluble proteins of the haemolymph, ovary and eggs of the honey bee were separated by electrophoresis on cellulose acetate foils and on polyacrylamide gels. The predominant haemolymph fraction (60–80%) is a female-specific protein. Corresponding fractions are found in the ovary and in uncleaved eggs. According to the results, it is highly probable that these fractions represent the yolk material or vitellogenin. InApis, this vitellogenin is represented by only one protein band which carries no carbohydrate components. The haemolymph titre of vitellogenic protein depends on the physiological state of the female bees. In the worker bees, haemolymph yolk proteins are detectable only during the nurse age, whereas in queens they can be found throughout the year. It may be noted that in the mated and egg producing queens the concentration of vitellogenin in the haemolymph is lower than in virgin queens and in adult non-laying queens. The rate ofin vivo protein synthesis was determined by injecting a mixture of14C-amino acids and measuring the radioactivity in pherogram bands using a methane flow counter. In the actively laying queen the rate of vitellogenin synthesis is 3 times higher than that of the non-sex-specific blood proteins. Approximately 85% of the labeled proteins which are released from the fat body are yolk material. In contrast to other insects, non-laying queens were also found to synthesize vitellogenin; however, the rate did not exceed that of the other serum proteins. The fate of yolk material in such females is unknown. In the ovary, synthesis of the euplasmic proteins occurs at a rate similar to that of the nonspecific haemolyph fractions. The appearance of radioactivity in the ovarian yolk is delayed compared with all other proteins. This indicates that these proteins are labeled byde novo synthesis, whereas the yolk is not built up within the ovary. This conclusion is further supported by the fact that the increase in specific radioactivity of ovarian yolk proteins occurs at a time when free14C-amino acids are no longer available in the haemolymph. Following the maximum intensity of labelling of yolk proteins the specific activity declines. From the data it can be estimated that the period of vitellogenesis for a single follicle is 2 days; 2 additional days of maturation, during which glycogen synthesis and chorion formation occur, are required before oviposition.

Notes: Summary When extraembryonic egg material is placed apart from prospective diapause germ anlagen or early germ bands, it will stimulate their development without dormancy via the medium. This method of a bipartial systemin vitro (21° C) helps to analyze the regulatory mechanisms involved in the egg diapause ofBombyx mori. 1. In preliminary experiments, a culture medium free of egg extracts but containing foreign proteins (LYS) proved useful, since 100% of the test germs reached dormancy in the absence of stored egg material. Mitoses decrease and morphogenesis decelerates until the stage of the fully segmented germ-band is reached, which means the end of the prediapausal period. 2. When eggs were opened they developedin vitro without egg diapause. One may assume that the access of free oxygen activates some regulatory mechanisms permitting development without dormancy (nondormancy=Nd). In addition, the separate deposit of chorion, serosa and yolk cells (CDS Depot) will in any case prevent dormancy. Thus, the factors responsible for egg diapause must be sought in the extraembryonic egg system. A direct contact between the extraembryonic action-system and the embryonic reactionsystem is not a prerequisite. TheLYS medium without deposits offers sufficient oxygen to the test germ. Therefore the prospective diapause germ possesses a tendency to dormancy, according to its reaction norm. The potency to stimulateNd was tested with various depotmaterials (C, D, S, CS, DS, CDS) removed from eggs during prediapause (21° C), diapause (3° C) and post-diapause (returned to 21° C for 4 days). Each material produced a specificNd rate.In vitro, the test germs can progress in their organogenesis optimally to the stage of a small larva. The means of a collective effect in development are determined and related to one of the nine possibledegrees of organogenesis. 3. In comparison to serosa and chorion, yolk material has the highest mean both inNd rate (68 %,n=219) and degree of organogenesis. Surprisingly, cell-free chorionic material prevents dormancy development in 55% (n=296). As compared to theD Depot, the combination ofDS elicits a higherNd rate (79%,n=234), which is only surpassed by theCDS combination (100%,n=76). In comparison toS Depot(44%,n=294) theNd rate of aCS Depot reaches only 37% (n=161), presumably due to a restriction of the experiments to young material only. Probes, tested separately according to germ anlage or germ band, showed that there was no influence of the operational age of the test germ on theNd rate. 4. However, theNd-stimulating potency ofC, D, S, CS andDS depends on the operational age of the donator egg. Yolk material starts out having a highNd effect, decreasing with pre-diapausal age and staying relatively high in diapausal age. Similar changes are observed in the combination of yolk and serosa. TheNd rate of chorion starts low, increases steeply with the operational age and remains rather uniform. TheNd rate of serosa increases steeply in the stage critical to the beginning of egg diapause (dish-like germ anlage), decreases after pre-diapause and increases again after the minimal period for diapause (3 months at 3° C). HigherNd rates are observed whenS, D, andDS Depot were returned to 21° C for 4 days.D Depot has the maximal potency favouring organogenesis at the dish-like germ anlage stage. 5. The following subjects are discussed: the results of Chino (1957, 1958) on glycogen metabolismin ovo, the findings of Okada (1971) on the development of de-chorionized eggs under paraffin oil and our ownin ovo observations on the ultrastructural changes in the chorion, the mitotic activity before and after diapause and the distribution of glycogen in germ, yolk cells and serosa. These facts can be utilized to formulate a concept of the physiological phases of egg diapausein ovo: Egg diapause begins during a critical stage of the germ anlage with a reaction between serosa and chorionic material, which reduces the rate of oxygen consumption. Under these conditions, glycogen is metabolized into sorbitol and glyoerol. The physiologicalprophase of egg diapause is terminated, when the germ-band reaches dormancy. Diapause begins (e.g. at 3° C) with themesophase, during which the metabolism of glycogen continues decreasingly. Now glycogen is found only in the germ.Metaphase may begin with the re-uptake of oxygen, which starts the re-synthesis of glycogen from sorbitol and glycerol via oxydation and phosphorylation. However, the exposure to cold (3° C) will inhibit mitosis in the dormant germ band. In thetelophase of egg diapause, after terminated resynthesis, the dormant germ can remain in quiescence. When exposed to 21° C during the embryonic post-diapause period, it consumes the stored glycogen. If the high temperature starts prematurely during the mesophase, no embryo will hatch. However, when high temperatures set in during the metaphase, glycogen resynthesis and glycogen-breakdown in embryogenesis will compete and thus the hatching rate will be low. 6. Assuming that in the depot experimentsin vitro at 21° C and with free access of oxygen, glycogen metabolism can be considered one parameter of theNd rate, a satisfactory explanation of our experiments can be offered. With aCDS Depot,Nd stimulatory mechanism will always work satisfactorily, assuming a considerable resynthesis of glycogen of previously cold-exposed depot material.Nd rate ofD Depot will first follow the glycogen parameterin ovo; when removed from diapause, it may be capable of the resynthesis of glycogen. This will also explain the correspondingNd rates of theDS Depots. There is no correlation between theNd rates ofC Depots and the glycogen parameterin ovo. S Depots acquire a dependency on the glycogen parameter, which is independent of exposure to high temperature and oxygenin vitro. Further investigations on the glycogen metabolim of the depot materialin vitro are necessary to clarify these hypotheses. 7. The observations on the physiological phases inBombyx may also hold true for egg diapause of other insects. Various experiments with eggs of other strains ofBombyx with different reaction norms may substantiate our present conclusions. The enzymatic basis of the regulatory mechanisms with special regard to chorion should receive further clarification.

Notes: Summary Experimental associations of gastric epithelium of the Rabbit foetus with homologous or heterologous mesenchyme, separated by membrane filter or “partially” associated, permit us to prove the existence of two types of inductors. The first factor induces the epithelial morphogenesis. It is thermostable and highly diffusible. The second factor, organospecific, is more or less favorable to the differentiation of the gastric epithelium according to the nature of the mesenchyme. Lightly diffusible and thermolabile, it is elaborated in the cytoplasmic phase of the mesenchymal cells.

Notes: Summary 1. After implantation of an imaginal wing disc a mirror-image duplication of the disc is formed, starting with the development of a fold at the back edge of the basic region of the implanted wing disc. 2. After implantation of an imaginal wing disc the host's pupation is delayed, the duration of the delay diminishing with the age of the regenerate. 3. Implanted parts of wing discs also duplicate. In this case, too, the duplication starts with the formation of a fold in the basal region. 4. No regenerate is formed, if the implant comprises no material from the basic region. Missing distal parts are not replaced during the host's phase of growth; they are, however, replaced during the phase of the prepupa. 5. If the implant contains material from the basic region, a regenerate always develops. If the basic region is complete, a whole wing disc is regenerated; if it is not complete, only a duplicate of the implant is formed. 6. Not before the 4th day is the regeneration fold finally determined. 7. The regenerate of the implant always consists of fewer cells than a regenerate of the same age in the host. 8. Implanted duplications do not lead to regeneration. On division of such a duplication along its axis of symmetry two new mirror-image duplications are formed (Verklonung). 9. Implanted wing discs which have been incised down into the basic region can give rise to a treble formation besides a normal regenerate. Transplanted treble formations do not duplicate; they only form a normal regenerate. 10. The transplantation of the upper layer of cells leads to the formation of two complete imaginal wing discs. A transplant from the lower layer of cells only duplicates itself. 11. The formation of lacunae is limited to the upper layer of cells. 12. Metamorphosed mirror-image duplications are not inverted. The regions which produce the articular portions are determined by implanted parts of wing discs.

Notes: Summary 1. In the paedogenetic gall midgeHeteropeza pygmaea, embryonic growth is at the expense of maternal tissues. The possibility of culturing egg folliclesin vitro throughout the entire period of embryonic development allowed the filming of embryogenesis. In the present paper development, growth and degeneration of egg folliclesin vitro (at 25° C) are analysed by time-lapse film. 2. During development of the mature egg follicle up to germ band formation, the yolk globules undergo alternative periods of oscillation and rest within the yolk syncytium. During the periods of time in which the yolk globules are at rest, cleavage divisions take place. All egg follicles analysed showed 13 resting periods which corresponded to the 13 cleavage divisions. A comparison with other investigations indicates, that oscillation of the yolk globules is not required for the migration of the nuclei, but is connected with a special function of the yolk syncytium in paedogenetic gall midges. 3. From the 1st until the 6th cleavage division the average duration of the mitotic cycle decreases from 75 to 50 minutes; from the 6th until the 13th cleavage division it increases to more than 3 hours. 4. Blastokinesis, i. e. germ band extension and germ band retraction, in all probability is the consequence of autonomous movements of the germ band and not of a morphogenetic effect of the yolk syncytium. 5. Egg follicles from different preparations show varying rates of development and growth whereas egg follicles within one culture drop develop and grow with the same rate although they may not be at exactly the same stage of development. 6. In certain stages of development (cleavage, germ band retraction and dorsal closure) the increase in length of the egg follicle is discontinuous. During germ band retraction many egg follicles show up to 7 elongations and contractions, which may amount to as much as one fifth of the egg follicle length. The period of time of one elongation-contraction cycle is between 1 1/4 and 2 3/4 hours and increases by 1/4 hour with each new cycle. At the same time as the egg follicle length increases, its width decreases and vice-versa, suggesting that the increase in volume is continuous. 7. Measurements of two egg follicles at the blastoderm stage revealed rhythmic fluctuations in length which amounted to no more than one fiftieth of the total egg follicle length. There may be as many as 60 such fluctuation cycles, each of which has a constant period of about 15 minutes. The endogenous process underlying these fluctuations is obscure. 8. The egg follicles which degenerate in culture are generally the smaller and less developed ones in any given preparation; however, until their sudden degeneration, they show the same rate of growth and development as the non degenerating egg follicles. 9. The extraordinary mode of paedogenetic egg development ofHeteropeza is interpreted as a displacement of embryogenesis into oogenesis.

Notes: Summary 1. The anatrepsis movements of the cricket germ band were analyzedi by timelapse micrography and by mechanical manipulation of the egg system. The behavour of isolated groups of germ band cells was recorded in vivo and in vitro. 2. The first phase of anatrepsis is characterized by 7–9 slow peristaltic waves passing within the yolk system towards the posterior egg pole (velocity 26–42 μm/min). 3. During this phase, the germ band moves backwards on the yolk surface. Its posterior end passes the posterior egg pole and then moves on anteriorly along the dorsal midline of the egg. The movement of the germ band is slowed down or reverts its direction temporarily whenever a peristaltic wave of the yolk system approaches the posterior egg pole. 4. In the second phase of anatrepsis, the posterior end of the germ band steadily (1.2 μm/ min) moves along the dorsal midline towards the anterior egg pole, thereby pushing its way in between yolk system and serosa. The remainder of the germ band does not follow suit along the yolk surface of the posterior egg pole but rather takes a short cut through the yolk system which meantime has been divided into yolk cells. 5. If the germ band is cut transversely during anatrepsis, only the part embodying the posterior end of germ band is able to continue movement. 6. Cells from the posterior end of the germ band display pulsating movements when isolated in vitro or in vivo. Cells from other germ band regions do not display such movements. 7. The results indicate that in the cricket egg anatrepsis of the germ band is not, as demonstrated in some other insects, due to pulling forces exerted by the yolk system, but rather appears to be caused by active locomotion of the posterior end of the germ band. Cells located there probably “crawl” along the serosa and pull the germ band trailing behind. The peristaltic waves in the yolk system are thought to ensure close contact between serosa and germ band when the latter passes the curvature of the posterior pole region. Yolk peristalsis is also likely to facilitate movement of the passively transported parts of the germ band.

Notes: Summary 1) The influence of reagents affecting SH or SS groups on morphogenesis has been studied in metamorphosing larvae and in regenerating adult hydranths. The thiol challenges evoke and enhance predominantly the differentiation of basal structures. 2) In larvae undergoing metamorphosis the SS-reducing agent Dithioerythrit (0.12–0.25 mM) brings about a prolongation of the subtentacular part of the body column. Dimercaptopropanol (0.19 mM), among other thiol challenges, enhances specifically stolonization giving rise to highly enlarged stolons. Under the influence of the oxidizing Kosower reagent Diamide (0.075–0.15 mM) transforming larvae develop a hypertrophied hydrorhiza which grows as a closed stolon-plate from the outset. In this way the primary polyps prematurely acquire the developmental state of sexual colonies. A correlation between the rH-values and the particular morphogenetic influences could not be established. 3) According to these “vegetalizing” influences on metamorphosis the thiol challenges cause regenerating hydranths to engage, in contrast to untreated controls, in differentiation of basal structures. The hydranths develop, though only in few cases, basal structures (stalks, stolons), whereas basal parts normally are never restored. In most cases, however, Diamide and especially dimercaptopropanol impose stolonial properties on hydranths as a whole. Such hydranths transform into giant stolons and secrete a periderm without first changing their outward appearance. Thus their state of differentiation becomes totally repolarized. 4) Tryptic dissociation exerts similar effects. Since all thiol reagents, at least in high doses, lead to the separation of the ectoderm and endoderm and to a partial dissociation of the tissue, it is suggested that the enhancement of basal development and the repolarization of the state of differentiation might be due to changes in cell adhesiveness and membrane properties.

Notes: Summary The synthesis of esterases was analysed in the ovariole of the milkweed bug using electrophoretic and histochemical methods. We found a total of 12 esterases from whole ovaries. Using the inhibitors p-hydroxymercuribenzoate, diisopropyl phosphorofluoridate and eserine, 3 of the bands were classed as acetylesterases, 7 carboxylesterases, and 2 arylesterases. No change in esterase patterns occurred during oogenesis. The esterase activity in the follicular epithelium was primarily arylesterase and carboxylesterase. A carboxylesterase was also identified from the central region of the follicle cell. The yolk cells contained mainly carboxylesterase. There was an apparent activation of enzyme activity following pre-treatment with eserine.

Notes: Summary Wild-type nuclei from eggs ofDrosophila melanogaster at various developmental stages and from different regions of the egg—cleavage nuclei, pole nuclei from preblastoderm, and lateral nuclei from syncytial blastoderm—were singly implanted into unfertilizedy w sn 3 lz 50e eggs to determine their developmental potencies. All three types of transplanted nuclei were almost equally effective in initiating development of unfertilized eggs. Development was arrested in one of five critieal embryonic stages or in one of the three larval instars. The frequency of individuals reaching a distinct stage was approximately the same for all three types of donor nuclei. The stage-specific pattern of defects was independent of the type of nucleus transplanted. The deviations from normal development were broadly similar to those seen in controls developing from fertilized eggs which had only been punctured or into which cytoplasm had been injected. Many defective embryos also occurred in these control experiments. These and other observations indicate that a large proportion of irregularly developed individuals found after nuclear transfer can be ascribed to loss of egg material, disturbances in the internal organization of the egg during nuclear implantation, and the difficulty the implanted nucleus has in adjusting to the autonomous processes within the egg, such as the formation and migration of cytoplasmic islands. Some of the defective embryos and larvae originating from nuclear transfer were implanted into adult hosts. After culture for 14 days the early embryonic stages had formed several larval structures, and the late embryonic and larval stages had developed all larval organs. The proliferated imaginal primordia of thesein vivo cultured embryos and larvae, as well as the imaginal disks of the third instar larva, were then implanted into larval hosts with which they passed through metamorphosis and differentiated into imaginal structures. All three types of donor nuclei were capable of producing all adult structures derivedin situ from imaginal disks. The phenotype of these structures waswild-type, thus demonstrating their origin from the transplanted nuclei. The problem as to why not all transplanted nuclei initiated development, and why development after nuclear transplantation was arrested at the third larval instar, at the latest, is discussed.

Notes: Résumé Les expériences que nous avons réalisées nous ont permis d'étudier le rôle de l'absence du gaz carbonique dans l'atmosphère où se trouve l'Insecte. L'une des deux femelles deBombus est introduite dans une cellule microcalorimétrique en atmosphère normale, l'autre femelle dans une cellule dont l'atmosphère est dépourvue de gaz carbonique. Dans l'expression des résultats, je considère d'abord les indications fournies par la forme des enregistrements. Afin d'apporter une plus grande précision dans l'interprétation des enregistrements, j'ai effectué une étude quantitative de la thermogenèse. Les résultats concernant l'influence de la température sur la thermogenèse des reines de Bourdons sont généralement conformes à ce que nous connaissons de la stimulation du métabolisme thermique par une élévation de la température chez la plupart des Poïkilothermes. On peut noter, qu'à température égale, les reines deBombus terrestris ont une thermogenèse relative supérieure à celle des reines deBombus lapidarius. D'autre part, pour chacune des espèces considérées, les valeurs thermogéniques des reines deBombus sont plus élevées — à une exception près — lorsque celles-ci sont placées en atmosphère dépourvue de gaz carbonique. En conclusion, l'absence de gaz carbonique dans l'atmosphère de la cellule microcalorimétrique ne modifie pas profondément le niveau des échanges respiratoires des reines deBombus, dans les limites de mes expériences.

Notes: Résumé L'activité de l'hormone juvénile (JH) est mise en évidence à partir d'extraits de contenu rectal d'ouvriers et de soldats et d'exsudat anal de reines de termites,Microtermes sp.,Microcerotermes beesoni (Snyder),Odontotermes obesus (Rambur),O. qurdaspurensis (Holmgren) etO. assmuthi (Holmgren), ainsi que du champignonTermitomyces sp. qui est présent dans la termitière. La signification possible de JH provenant de différentes sources, castes de termites ou champignons, est discutée.

Notes: Résumé Des études du mécanisme de la détermination des castes chez les termites ont été faites chezNeotermes jouteli (Banks), (Famille Kalotermitidae), de la Floride du sud. On a trouvé que les pseudergates de cette espèce peuvent répondre à l'isolement par une production rapide et importante de sexués néoténiques (SRs). De la même façon, la production de soldats s'observe chez des groupes dont on a enlevé cette caste. L'intensité avec laquelle les SRs se sont produits (dénommée IR) varie avec la colonie d'origine des pseudergates. Une IR basse est trouvée chez des colonies qui avaient des grands pseudergates et qui produisaient des ailés. Une IR haute est trouvée chez des colonies qui avaient des petits pseudergates et qui ne produisaient pas d'ailés. On conclut que l'IR tombait avec l'âge de la colonie d'origine. Chez les colonies d'IR haute, tous les pseudergates étaient capables de se transformer en SRs. Chez les colonies d'Ir basse, les formes larvaires de la même taille que les pseudergates dans les colonies d'IR haute étaient complètement incapables de se transformer en SR. Les sexués mâles et femelles se sont trouvés jouer des rôles différents dans l'inhibition de la transformation en SR chez des groupes isolés. La femelle a bloqué complètement la formation de SRs femelles et, en partie, la formation de SRs mâles. Le mâle a bloqué, en partie, la formation de SRs mâles et de SRs femelles au même point. En plus, une paire de sexués du même sexe était aussi inhibitrice qu'une paire bisexuelle. Le nombre de SRs produits par un groupe de pseudergates isolés croissait avec le nombre d'heures par jour d'absence des sexués. Les pseudergates femelles répondaient moins à l'absence des sexués que les mâles. La transformation en SR ne pouvait pas être inhibée si on limitait l'alimentation des pseudergates isolés au papier de filtre imprégné de gouttes fécales obtenues de 25 paires de SRs par jour. Les sexués avec des anus bloqués étaient complètement inhibiteurs pour une semaine après que des témoins isolés commençaient à se transformer. On a donc conclu que l'alimentation proctodéale probablement n'était pas le mécanisme de transmission des phéromones inhibitrices postulées.

Notes: Résumé Ce travail concerne létude écologique de la fourmi lignicole,Camponotus vagus Scop. Il a été réalisé dans la zone forestière située en arrière-pays d'Antibes, à une quinzaine de kilomètres de la côte, ainsi que dans les îles de Lérins (en face de Cannes). Les relevés périodiques nous ont permis de mettre en évidence certaines causes, entraînant le choix d'un site de nidification dans un biotope donné. Ainsi, les critères suivants ont été utilisés pour interpréter la présence et l'abondance des nids de cette espèce, dans sa zone de répartition: - nature du sol, pente, exposition; - végétation et matériaux disponibles (en fonction de l'âge des peuplements forestiers, incendies, etc…); - interventions humaines. L'analyse de l'architecture des nids nous a conduit à dégager un certain nombre de types distincts en tenant compte de la nature des matériaux utilisés, du mode de creusement et de l'âge des colonies.

Notes: Résumé On décrit des observations sur l'écologie de quatre espéces de fourmis aux îles Salomon. Il s'agit des fourmis des espèces indigènes d'Oecophylla smaragdina etIridomyrmex cordatus, et des espèces introduites d'Anoplolepis longipes etPheidole megacephala. L'auteur donne de brefs exposés sur la structure de colonie, sur le terrain de nid, sur l'habitat et sur les ennemis de chaque espèce. Toutes les espèces disposent d'une vaste étendue de nourriture, mais les sources principales en sont les miellats, retirés des Homoptera, et la proie. Le miellat est très important comme partie constituante de la nourriture des espèces de fourmis indigènes, qui montrent des rapports très proches avec les Homoptera endémiques et indigènes. Les deux espèces de fourmis introduites dépendent plutôt de la prédation, tandis qu'en Afrique, leur région d'origine, c'est le contraire. Dans un examen des quatre espèces, on a traité des sujets suivants: la résistance au dessèchement, la relation entre la température et la vitesse de mouvement des butineuses, et les préférences de température et d'humidité.Oecophylla smaragdina supporte bien la variation des deux facteurs,P. megacephala est adaptée le mieux aux températures relativement basses, tandis queA. longipes s'adapte le mieux à une température élevée, bien qu'elle soit prédisposée au dessèchement. C'est en observant les heures de la journée où les espèces butinent qu'on se rend compte de ces différence:O. smaragdina est diurne,P. megacephala etI. cordatus sont nocturnes.A. longipes est crépusculaire, et habituellement limite son activité diurne pendant les périodes de basse humidité, et son activité nocturne pendant les périodes de basse température. L'auteur a conclu que les espèces indigènes s'adaptent mieux aux conditions des îles Salomon en ce qui concerne la distribution de nourriture et l'entourage physique et climatique.

Notes: Résumé Au cas où il y a deux rayons et soit un seul, soit un petit nombre d'ouvrières, on constate que le rayon sans couvain attire moins les ouvrières que celui operculé (cocons ou larves). Pour ce qui est d'un petit nombre ou d'un grand nombre de larves, ou encore des larves de reines ou de non-reines, l'attraction est égale pour chaque ouvrière. L'ouvrière ne se trouvant pas sur le rayon se déplace au hasard. De plus, quand elle est sur un rayon elle a tendance à rester avec le premier groupe de larves qu'elle trouve. L'examen des observations effectuées sur le terrain montre que les adultes se groupent la nuit, au fond du nid. Six nids, contenant des colonies entières ou presque entières, ont fait l'objet de plusieurs observations pendant une période de trois ans. Durant la même période, les résultats ont été enregistrés. Dans tous les cas, un rayon dominant s'est établi dans un bref délai. Ce rayon avait un plus grand pourcentage d'ouvrières que tout autre, et comportait généralement la reine. Le rayon dominant contenait toujours du couvain; il se trouvait le plus près de l'entrée du nid (ou bien était parmi les plus près); il recevait le plus grand nombre de butineuses, et des ouvrières s'y groupaient plus fréquemment que sur d'autres rayons. Il est possible d'établir un rapport entre le comportement des ouvrières lorsqu'elles se groupent sur un rayon, et la température ambiante. En effet, ce comportement a entrainé une hausse allant jusqu'à 29° C–32,5° C sur le rayon. L'attention que prêtait une ouvrière à la larve augmentait à mesure que le nombre d'ouvrières sur son rayon augmentait. On traite dans cet article du comportement observé lors d'un groupement, les raisons et les conséquences; ainsi que de l'apparition d'un, rayon dominant et de la position de celui-ci dans le nid.

Notes: Résumé L'auteur a utilisé différentes techniques de la coloration et la microscopie sur fond noir pour l'étude histologique du complexe neuro-endocrinien de l'abeille. On distingue deux types de cellules dans la pars intercerebralis. L'examen ultrastructural révèle qu'un troisième type de cellule est identique au second type, mais la technique appliquée au cours de ces travaux différencie encore un autre type de cellule (publication en cours de préparation). Le trajet des axones partant de la pars intercerebralis réclame une attention particulière, la présence de trachéoles à forte réaction phloxinophile pouvant y faire croire à la présence d'une sécrétion phloxinophile. La même technique de coloration appliquée après fixation en solution de Carnoy ne donne aucune différenciation de la sécrétion hématoxyline-positive en une fraction soluble et en une fraction insoluble dans l'alcool. La coloration à la paraldéhyde-fuchsine selonEwen (1962) confirme les résultats de la coloration selonGomori. La coloration à la paraldéhyde-fuchsine selonHalmi (1952) ne permet pas de déceler un produit de sécrétion dans les cellules des corpora allata de l'abeille (ouvrière). Les éléments névrogliques du système neuro-endocrinien de l'abeille domestique sont nettement différenciés par la coloration à la fuchsine acide Light Green selonAlzheimer. L'éclairage sur fond noir révèle que les cellules de la pars intercerebralis de l'abeille ont à un degré élevé la propriété de diffuser la lumière. Certaines autres parties du complexe cérébral présentent cependant le même phénomène, de sorte que cette technique est sans utilité pratique pour la différenciation des cellules neuro-sécrétoires.

Notes: Résumé 1. La nomenclature dressée parOtto [16] pour la description des phases des ovaires chez les fourmis ouvrières deFormica polyctena n'est pas suffisante pour les ouvrières deFormica rufibarbis. 2. Otto analyse la croissance et la réduction de l'ovaire d'après le stade de développement des œufs les plus vieux. En ce qui concerne la réduction de l'ovaire des ouvrières deF. rufibarbis on doit faire la différence entre une transformation régressive des œufs les plus vieux et entre une transformation régressive du Germarium et des Oocytes. Une réduction de l'ovaire n'est présente que quand les œufs et en même temps le Germarium et les Oocytes sont transformés régressivement. 3. Chez les animaux de plein champ et ceux du laboratoire j'ai trouvé des ovaires qui différaient des phases E de la nomenclature dressée parOtto par des transformations comme on ne les trouve qu'en cas de réduction de l'ovaire. J'ai appelé ces stades: Er. 4. Une phase V, commeOtto la décrit pourF. polyctena, n'est trouvée que rarement. Plus souvent au contraire on trouve des ovaires qui ne différaient des phases V que par des «Gelbkörper» ou par des œufs déformés. Ces ovaires furent distingués des phases R1 comme phase R1v et je le considère comme la vraie phase V puisqu'on a pu prouver que les ouvrières qui ont des ovaires R1v peuvent pondre des œufs. 5. La dépendance entre le point du développement des ovaires et l'action reconnu parWeyer a pu être vériflée pourF. rufibarbis. La plupart des animaux du service extérieur ont des ovaires rétrogradés et une grande partie des animaux du service intérieur a des ovaires bien développés. 6. On a pu vérifier pourF. rufibarbis une dépendance saisonnière de l'apparition de certaines phases d'ovaires chez les animaux du service intérieur. Dans les mois de juin, juillet et août, la phase R1 apparaissait le plus souvent. En automne la phase Er augmente et la phase R1 diminue dans la même mesure ce qu'on a pu observer non seulement dans les nids du plein champ, mais aussi dans les nids du laboratoire. Au commencement de l'hiver les ouvrières de toutes les phases de développement régressaient leurs ovaires. 7. On a pu vérifier de nouveau que les ouvrières deF. rufibarbis pondent des œufs qui peuvent se développer en mâles (règle deDzierzon). 8. En général on a pu vérifier la dépendance entre les phases des ovaires et les corps gras, qui est connue pour d'autresFormica. An laboratoire on a trouvé des différences: malgré l'ovaire régressé, les animaux avaient des corps gras bien développés. 9. On a pu vérifier les résultats trouvés dans la littérature (1 à 4 ovaires par chaque moitié du corps) pour les 1 573 ovaires préparés. 10. On a pu développer un nid artificiel qui rendra possible un élevage intensif dans les conditions du laboratoire et qui peut ètre utilisé aussi pour d'autres applications comme par exemple pour des expériences d'infestations avecDicrocoelium dendriticum.

Notes: Summary An analysis of the global nature of the atmospheric electric field is presented on the basis of comparison of measurements on the research vessel, Hakuho-Maru, on the Mid- and South-Pacific Ocean, with those at Syowa Station in Antartica and on two vessels on the Mid-Atlantic Ocean. The comparison of daily averages gave a different type of latitude dependence, which was characterized by a gradual decrease toward the antarctic region. Diurnal variations at these globally representative stations on the same day were checked with each other for the first time, and the correlation between them was found much higher than that between land stations. The regional effect, which might depend on the distance from the thunderstorm area, was not evidently detected. So the influence of the generator area was considered to propagate over the entire globe without significant attenuation.

Notes: Summary During the International Geophysical Year, 1958, and extending into 1959, the atmospheric electric field, current, and conductivity were recorded at Thule, Greenland (78°N). During the International Year of the Quiet Sun, 1964, records of the atmospheric electric field were obtained at the Amundsen-Scott Station at the South Pole (90°S). The diurnal variation averaged over the year of the normalized current at Thule and the normalized field at the South Pole show a surprisingly good agreement. These two curves combined into one represent the world time variation of the air-earth current (or field) in the Polar regions. Compared with the oceanic diurnal field variation obtained at the Carnegie ship cruises, the Polar curve shows a very similar shape but a much reduced amplitude. The maximum and minimum in the Polar regions are 1.07 and 0.92. The corresponding values on the oceans are 1.20 and 0.85. The difference is greater than the measuring error or statistical scatter and has to be accepted as real. No conclusive explanation of the deviation of the two curves can be offered. The diurnal variation of the Polar data averaged over a season displays very smooth and similar curves during Northern autumn and winter. The spring and summer curves show a much more detailed structure with several maxima and minima. It is somewhat unexpected that the summer curve with a variety of fine structure is the flattest curve of all seasons. The minimum never drops below 0.95, and the maximum does not exceed 1.06. If the data are broken down into hourly means averaged over one month and split into an Arctic and Antarctic part, the similarity between corresponding curves of the same month vanishes for the months of January to July. This may partly be due to the fact that the number of fair-weather days of the individual month is too small to obtain a representative statistical average. Usually averaging over seven or more days is necessary for the oceanic pattern to emerge. However, there is a strong possibility that another agent besides the worldwide thunderstorm activity modulates the global circuit. The seasonal differences, and especially the difference between Arctic and Antarctic pattern, point to such a conclusion.

Notes: Summary Results of measurements of the atmospheric electrical conductivity and potential gradient made during the sixth Scientific Cruise of the Indian Oceanographic Ship INS Kistna in the Bay of Bengal during February–March 1963 are presented. Observations were made when the skies were generally clear and the sea calm, in the geographical area 8°N to 17°N and 80°E to 95°E, on the outward journey of INS Kistna from Madras (80°E, 13°N) to Port Blair (93°E, 12°N) and on the return journey to Madras. Over the ocean where there are no local sources of pollution, the measured values of conductivity and potential gradient are in agreement with theoretical values, assuming that an ion equilibrium exists, that ions are destroyed primarily by collision with small ions of opposite sign and that small ions are produced only by cosmic radiation. The values of electrical conductivity obtained are generally of the same order as those to be expected from theoretical considerations and in general agreement with those obtained during the Carnegie cruises in the Indian Ocean in 1920. There are, however, significant variations near the coast where the electric structure above the ocean is affected by continental sources of pollution. Conductivity values near the land are about half that in the unpolluted air over the ocean but prevailing winds prevent the extension of pollution beyond 100–200 km from the coast in this season.

Notes: Summary The dynamic spectra of the atmospheric ions with mobilities between 3.2×10−4 m2/V sec and 1.3×10−8 m2/V sec were obtained in the clean and the polluted atmosphere. Based on the results, the size spectra of the submicron aerosols were deduced which show that the distribution function in Junge's expression increases in proportion to the radius of particle. Very rapid progress of the atmospheric pollution by the submicron aerosols was inferred at a rural country. The concentration of submicron aerosol particles at the site was found to have been increasing at the rate of being doubled every three years since 1964.

Notes: Summary Elastic wave propagation problem has been studied in the composite medium — a gravitating liquid layer overlying an elastic half-space. Assuming moving normal pressure load on the free surface, an attempt has been made to study the order of disturbance on the earth's surface. In the discussion asymptotic values of the displacement, components have been considered for small values of the parameter.

Notes: Summary The aim of this work is to examine the critical loci which govern the limits to the depths to which a Rayleigh wave can penetrate into a Half-space. Both interior and surface sources are considered. The corresponding critical regions for the existence of these waves play a vital role in more complicated problems such as the calculation of the reflection and transmission coefficients of Rayleigh waves in a wedge.

Notes: Summary Azimuths and angles of incidence have been calculated from short-periodP-wave amplitude components of 197 events recorded at Umeå, Sweden, near the center of Pleistocene glaciation in Fennoscandia. Anomalies in both sets of data indicate significant departure from a spherically symmetricP-velocity structure. A model incorporating five parameters-strike and dip of equivelocity planes, velocity at the Earth's surface, and at the top and bottom of the heterogeneous zone-is assumed and the parameters are optimized by a computer search. Results, both from the two independent sets of data-incidence-angles and azimuths-as well as from a combined setdirection consines-are mutually consistent and indicate rising equivelocity surfaces, or laterally increasingP velocity, to the ENE in the upper 100 or 200 km of the Earth in the neighbourhood of Umeå. An added refinement, consistent with the results, is an asthenosphere layer pinching out to the ENE, i.e. towards the point of present-day maximum uplift. A surfaceP-wave velocity of about 5.9 km/sec is indicated by the data.