La paléoflore autuno-stéphanienne de la région de Demnate(Est de Marrakech-Maroc)

The paleoflora described and pictured in this paper has been collected in two deposits of the area of Demnate: the OT6 bis drilling in the oriental Haouz and an exposure in the Rhojdamas (High-Atlas). Two completely different associations have been characterized: one hygrophilous and autochtonous of the «Stephanian type and the other mesoxerophilous and allochtonous (vegetation of the upland?) of the «Autunian type. In the OT6 bis drilling, the two floras alternate so that it is impossible to draw a precise boundary between the Stephanian and Autunian. In the Rhojdamas, only the Autunian flora has been identified. Such a combination of the two floras has similarly been recorded in several stephanian basins of the French Massif Central.     

Stratigraphie de la série tertiaire de Casamance (Sénégal)

The micropaleontological and sedimentological analysis of the cuttings and core-samples extracted from a certain number of borings conducted seaside Casamance, western Casamance and eastern Casamance (fig. 1), enabled the researches to determine Casamance stratigraphy and paleoecology during the tertiary period. The microfauna gathered (foraminifera and ostracoda) makes it possible to characterize the biozones P1 to P15/P16 followed by the biozones N1/N2 to N14, bringing into evidence the existence of Paleogene and Neogene which are separated by a gap of changeable amplitude.The sedimentological study has revealed the presence of a certein number of landmarks and lithologic mineralogical sets which seem to be constant in the studied boring.     

Cyanophyceae (Cyanobacteria) aérophiles de Nouvelle-Calédonie

This paper deals with the aerophytic Cyanophyceae from New Caledonia sampled by Prof. Dr A. Guillaumin from Paris, Dr M.G. Baumann-Bodenheim from Zürich, Dr H. Hürlimann from Winterthur and Prof. Baas Becking from Noumea. A total of 124 samples were studied, most of them collected on soil, stones, rocks and barks. The characteristics of these samples are given. Among species, varieties and forms, a total of 85 taxa were recorded. Among them three are new for science, Gloeothece neocaledoniense nov. sp., Hydrocoryne neocaledonica nov. sp. and Scytonematopsis neocaledoniense nov. sp. One new combination is proposed, Petalonema involvens var. elongata (Bourr.) nov. comb.     

Una nueva especie de Hypenia (Lamiaceae) de México

Hypenia violacea (Lamiaceae), a new species from Guerrero, Mexico, is described and illustrated. This species is characterized by glabrescent, coriaceous leaves, lax thyrsoid inflorescences with pedunculate and umbelliform cymules that have 3–6 violet flowers with corollas 0.8–1.6 cm long. The species is referred to the Southern American genus Hypenia.

---

Resumen  Se describe e ilustra Hypenia violacea (Lamiaceae), una especie nueva de Guerrero, México. Presenta hojas coriáceas, glabrescentes, inflorescencia tirsoide, laxa, con címulas umbeliformes, pedunculadas, con 3–6 flores por címula, flores de color violeta, de 0.8–1.6 cm largo. Las características observadas corresponden, en su mayoría, a Hypenia, un género de distribución sudamericana, por lo que se incluye en el mismo.

     

Composés bromés de Rytiphlea tinctoria (Rhodophyceae)

Four aromatic bromo compounds have been isolated from the ethanolic extract of Rytiphlea tinctoria after treatment with diazomethane: 2,4-dibromo-1,3,5-trimethoxy-benzene,5,6,3′,5′-tetrabromo-3,4,2′,4′,6′-pentamethoxydiphenylmethane, 5,6-dibromo-3,4-dimethoxy-benzyl alcohol and its ethyl ether. In addition to sterols, amino acids, this extract also contains quinonoid bromo-pigments which could play a rôle in photosensitisation of chlorophylls, a rôle normally taken by the phycobilins, in other Rhodophyceae.     

Modélisation de l'impact des mollusques cultivés sur la biomasse phytoplanctonique de l'étang de Thau (France)

A model coupling a 2D transport equation and a simple model of the nitrogen cycling was developed for the Thau lagoon (France). The model took into account the wind forcing on the hydrodynamism, the effect of the temperature on the biological processes, the input of the watershed area, the light dependence of the pelagic primary production and the prédation of the phytoplankton by the cultivated filter feeders. The model ran under two steady-state situations of wind with constant temperature and light values corresponding to spring weather conditions. Simulations showed that the biological flows were very sensitive to the wind. The budget of the nitrogen flows were computed for the three areas devoted to the filter feeder cultivation and the results highlighted the impact of cultivated oysters as a source of nutrients and an important nitrogen flow through the predation of phytoplankton.     

Ultrastructure de l'épithélium tégumentaire de Glossiphonia complanata (L.) (Hirudinée): cellules épithéliales et organes sensoriels de Bayer

Résumé Le tégument de Glossiphonia complanata comprend, outre les cellules épithéliales banales, de nombreux organes particuliers ou organes de Bayer, regroupés essentiellement sur la face dorsale de l'animal. Ils sont formés par une cellule apicale saillante enchassée dans une cellule musculaire en anneau.L'ensemble de ces formations est étudié du point de vue ultrastructural. Des cellules épithéliales partent des fibres nerveuses afférentes, sans doute vecteur des perceptions de stimuli mécaniques de pression au niveau du tégument; la réponse se faisant sans doute par la contraction de la cellule basale de chaque organe de Bayer, innervée par des fibres nerveuses efférentes, entrainant la saillie de la cellule apicale. Le hérissement de ces nombreuses papilles du tégument dorsal pourrait être un signal perçu par le partenaire sexuel, chez cette Hirudinée à fécondation hypodermique.

---

Ultrastructure of the integumentary epithelium of Glossiphonia complanata (L.) (hirudinea): Epithelial cells and sensory organs of bayer

Summary The integument of Glossiphonia complanata, built up by epithelial cells, contains numerous particular organs (Bayer organs), mainly on the dorsal side of the animal. They consist of a protuberant apical cell, which is surrounded by a ring-shaped muscle cell. All the integumentary formations are studied from an ultrastructural point of view. From the epithelial cells issue afferent nerve fibres, considered as vectors of the perception of mechanical stimuli of pressure at the level of the integument; the response no doubt operating by the contraction of the basal muscle cell of each Bayer organ, innervated by efferent nerve fibres, bringing forth the protrusion of the apical cell. The erection of these numerous papillae of the dorsal integument might be a signal perceived by the sexual partner, fecundation occurring in this group of leeches under the integument.

     

Infrastructure superficielle de la vésicule vitelline et du sac péricardique de l'embryon de Poecilia reticulata (Poisson Téléostéen)

Résumé Le microscope électronique à balayage montre l'existence d'un réseau complexe de microcrêtes à la surface de la vésicule vitelline et du sac péricardique de l'embryon de Poecilia reticulata. Cette étude permet également de préciser la localisation, l'aspect et la répartition des «cellules à chlorure» et de proposer un schéma tridimensionel de l'organisation infrastructurale de la paroi de la vésicule vitelline. Un choc osmotique détermine rapidement un mouvement d'étalement des cellules épithéliales sur la surface apicale libre des «cellules à chlorure». La signification de ces résultats est discutée en rapport avec le problème de l'osmorégulation embryonnaire chez les Poissons, en particulier chez les Cyprinodontes vivipares de la famille des Poeciliidae.

---

Ultrastructure of the yolk sac and pericardial sac surface in the embryo of the teleost Poecilia reticulata

Summary A complex network of microridges is revealed by scanning electron microscopical examination of the yolk sac and embryonic pericardial sac surface of Poecilia reticulata. This study also specifies the localization, aspect and distribution of the chloride cells. A tridimensional diagram of the ultrastructural organization of the yolk sac wall is suggested. Osmotic stress quickly induces an overlapping of adjacent epithelial cells on the free apical surface of the chloride cells. These findings are discussed in relation to the problem of embryonic osmoregulation in fishes and especially in viviparous Poeciliids.

Nous exprimons notre gratitude à Mme Neumann, Directeur du Laboratoire de Micropaléontologie de l'Université Paris VI, qui nous a permis d'utiliser le microscope électronique à balayage qui a servi à cette étude. Nos remerciements s'adressent aussi à Melle Aubry et à M. Saussé pour leur concours technique. — Les observations en microscopie électronique en transmission ont été effectuées au Laboratoire de Microscopie électronique appliquée à la Biologie du C.N.R.S.     

Techno-économie et signification culturelle de l’occupation moustérienne supérieure de Baume-Vallée (Haute-Loire)

The archaeological units of the Baume-Vallée rock shelter (Haute-Loire) in the South-East of the Massif Central, excavated by A. Laborde (from 1966 to 1973) then by J.-P. Raynal (from 1974 to 1996), have yielded abundant lithic assemblages attributed to the late Middle Paleolithic, characterized by a remarkable diversity of the raw materials used. The lithic industry of the upper units had previously been described as belonging to the Charentian facies lato sensu, then was attributed to the Ferrassie-type Mousterian. The technology and the techno-economic revision of its upper assemblage bring new information on the flaking mechanisms and the steps of the chaînes opératoires. These data tend to include this assemblage in the Levallois techno-complexes with scrappers often observed in late Middle Paleolithic of southeastern France.     

Evolution de la musculature desNéréidiens (Annélides polychètes) au cours de l'Epitoquie

Résumé Au cours de l'épitoquie des Nereidiens, les fibres musculaires longitudinales ne sont pas forméesde novo, à partir de cellules indifferenciées ou myoblastes, mais proviennent des fibres anciennes atoques. Celles-ci subissent une véritable dédifférenciation plus ou moins synchrone d'une redifférenciation. Les deux processus ne sont pas successifs mais simultanés, et une dédifférenciation complète est absente.Les premières cellules en évolution appartiennent à la couche musculaire externe; ensuite, les fibres des assises plus profondes se transforment à leur tour.Les transformations consistent en: 1) La dédifférenciation du bord interne ou coelomique de la fibre. Les structures contractiles disparaissent dans cette zone et de nombreuses particules de glycogène se différencient sans relation avec le reticulum endoplasmique ou les ribosomes. Aucun lysosome ou signe précurseur ne peuvent être observés avant la disparition des filaments contractiles et des éléments Z. 2) Le bord coelomique s'hypertrophie. Dans la région axiale de la fibre, de nombreuses mitochondries et particules et de glycogène remplacent le matériel contractile. Corrélativement, l'épaisseur des bandes A et I diminue. 3) La fibre hétéronéreidienne ou épitoque est constituée et présente deux parties: un cortex myoplasmique et une médulla sarcoplasmique, remplie de mitochondries et de glycogène. Le noyau renfermant un nucléole volumineux est situé dans une hernie sarcoplasmique latérale.

---

Evolution of muscles inNereidae (Annelida polychaeta) during Epitoky. III. Dedifferentiation of the longitudinal fibres

Summary During epitoky inNereidae, the longitudinal muscle fibres are not formedde novo from undifferentiated cells or myoblasts, but arise from the old atokous fibres. These undergo a true dedifferentiation more or less synchronously with a redifferentiation. The two processes are not successive but simultaneous and there is no complete dedifferentiation.The first cells that develop are in the outside muscle layer; then the fibres of the inside layers are transformed in their turn.The transformations consist of: 1) Dedifferentiation of the edge of the inner or coelomic fibre. The contractile structures disappear in this part and numerous glycogen particles differentiate, unrelated to endoplasmic reticulum or ribosomes. No lysosomes or precursory markings are observed before the disappearance of contractile filaments and Z rods. 2) The coelomic edge becomes enlarged. In the axial region of the fibre, numerous mitochondria and and glycogen particles take the place of the contractile material. Consequently, the thickness of A and I bands decreases. 3) The heteronereid or epitokous fibre is formed and shows two parts: a myoplasmic cortex and a sarcoplasmic medulla, filled with mitochondria and glycogen. The nucleus with a voluminous nucleolus settles inside a lateral sarcoplasmic swelling.

     

Influence comparée de l'(±)-acide abscissique,de la coumarine,de l'acide p-coumarique et de certains de leurs dérivés sur la croissance de la première feuille de blé

Summary The activities of (±)-abscisic acid and a number of compounds derived from p-coumaric acid and coumarin and their interaction with gibberellic acid in the control of the elongation of the first wheat leaf are examined. (±)-Abscisic acid strongly inhibits leaf growth in the presence as well as in the absence of gibberellic acid, but the inhibition is greater in the presence of gibberellic acid (3 g/l already have an observable effect). Among other compounds, only ferulic acid and coumarin significantly reduce leaf elongation, and they are effective only at high concentrations (1.44 · 10^-4 M/l).     

Palynologie des variants androgénétiques de Nicotiana plumbaginifolia (Solanaceae)

L'examen des grains de pollen de variants androgénétiques de Nicotiana plumbaginifolia a permis d'aborder une nouvelle approche de la variabilité des plantes cultivées in vitro. En plus de la morphométrie et de la MEB, techniques classiquement utilisées en palynologie, la mise en oeuvre de la spectrométrie X à sélection d'énergie et de la microfluorométrie de la sporopollénine, a permis de mettre en évidence des différences intraspécifiques très importantes pouvant aider à la compréhension de l'installation de la variation somaclonale.

Pollen grains of androgenetic variants of Nicotiana plumbaginifolia were studied using classical methods in palynology (morphometry, SEM) and by energy dispersive X-ray spectrometry or microfluorometry of sporopollenin can allow a new advance in variability studies in conjunction with in vitro plant production. It is also more interesting to study possible relationships between palynological parameters and ploidy level.     

Extracorporeal membrane oxygenation (ECMO) pour les syndromes de détresse respiratoire aiguë (SDRA) sévères Point de vue de l’anesthésiste réanimateur

Many problems concerning the work of anaesthesist and intensivist are evocated during the management of ECMO: indication, optimisation of artificial ventilation during ECMO, transportation of the patient and complications.The criteria of indication are now best known, but the vascular access (veino-venous or arterio-venous) are discussed depending of cardiac echographic evaluation but also splanchnic consequences. Artificial ventilation modalities are not completly validated and probably need a better individual exploration at bed.     

Découverte de vertébrés aquatiques présumés paléocènes dans les Andes septentrionales de Bolivie (Rio Suches,synclinorium de Putina)

The teleost fish Brychaetus and a dyrosaurid crocodilewere recognized among the aquatic vertebrates recently discovered in the northern area of the Titicaca lake (Bolivia). These fossils allow the presumption of a Paleocene age for the vertebrate bearing formation. The structural interpretation of this chronological data is discussed.     

Le genre RichterellaAvram (Ammonitina,Périsphinctidés) dans le Tithonique inférieur de la bordure ardéchoise (Sud-Est de la France): Dimorphisme et variabilité

Dimorphism in the genus RichterellaAvram is confirmedon the basis of material collected in Ardeche (South east France) principally in the beds of the Fallauxi zone, from the localities of Le Pouzin and Broyon. The microconch, R. richteri (Oppel), lacks lateral lappets but a ventral horn, formed by the strongly projected forward secondary ribs, is present. The macroconch is «Lemencia praerichteriDonze & Enay. These two forms are united in the same species, R. richteri, and then in the same genus, Richterella. The microconch, which is generally better preserved than macroconch in the studied material, shows a greater variability of ribbing than previously thought, due to the poor illustrations of the lectotype of richteri (reproduced here) which showed only dichotomous ribs. The genus Richterella loses its original dimorphic sense and since its origins and its possible derivations are unknown, it became a taxon defined on morphological bases. The forms from Ardeche bear a greater resemblance to the Spanish ones than they do to the Roumanian forms. The stratigraphical and faunal contexts of Richterella in Ardeche are discussed in this work.     

La faune malacologique des calcaires éocènes de la région de Sabarat (Pyrénées ariégeoises)

Limestone beds included in the «Poudingue dePalassou around Sabarat (Ariège) contain a Gasteropod fauna known since J.-B. Noulet's works (1857). The systematic inventory of the different localities and the paleontological study of the material collected prove that two successive and clearly different Mollusc faunas existed. The bartonian fauna with Ischurostoma formosum minutum (Noulet) and Biomphalaria vasseuri (Roman) is preceded by a lower lutetian fauna with Biomphalaria pseudoammonius (Scholtheim): in the latter, two paleoecological groups are opposed according to the sheltered channels of two kinds in which limestones beds have been built. Besides, the chronostratigraphic consequences imply that the middle part of the «Poudingue de Palassou has been formed from Lower Lutetian to Bartonian.     

Etude olfactométrique de l'action de diverses substances allélochimiques végétales dans la recherche de l'hote par Diadromus pulchellus (Hymenoptera,Ichneumonidae)

Résumé La recherche de l'habitat d'un hôte potentiel par D. pulchellus, endoparasite considéré comme spécialiste des nymphes d'A. assectella, est abordée chez les adultes femelles et mâles, en olfactométrie, par l'étude de leur comportement locomoteur. L'activité locomotrice et l'attraction sont ainsi analysées en présence de substances allélochimiques issues ou non de végétaux pouvant abriter un hôte. Que les composés soufrés testés soient stables ou non, ils ne déclenchent pas d'attraction chez les hyménoptères quel que soit leur sexe et le type d'olfactomètre utilisé, contrairement aux imagos du phytophage-hôte, A. assectella, attirés par les composés soufrés instables spécifiques du poireau. L'activité locomotrice des hyménoptères des deux sexes est stimulée par divers composés volatils soufrés de synthèse ou émis naturellement par les Crucifères et par les Allium consommés par les larves d'A. assectella. Les substances efficaces sont généralément stables et sont caractérisées par le groupement actif R-S-, à condition que R ne soit pas un allyle. Par ailleurs, des composés volatils non soufrés contenus dans des végétaux autres que les Allium et les Crucifères ne stimulent pas le comportement locomoteur des hyménoptères. Ces différentes observations permettent d'envisager que D. pulchellus est un spécialiste inféodé à des microlépidoptères s'alimentant sur des végétaux soufrés et non sur les seuls Allium.

---

Summary Searching the host habitat by the endoparasite wasp Diadromus pulchellus, considered to be a specialist of Acrolepiopsis assectella nymphs, is studied in females and males by analysis of locomotory behaviour in olfactometers. Thus, locomotor activity and attraction are studied in the presence or absence of air-borne volatiles emitted by plants able to shelter a potential host-moth. Stable and unstable sulphur compounds used do not release attraction in female and male ichneumonids whatever the type of olfactometer used. By contrast, phytophagous host adults are attracted by unstable specific sulphur compounds of the leek. Locomotor activities of D. pulchellus females and males are stimulated by various volatile sulphur compounds of synthetic origin or naturally occurring in Allium eaten by A. assectella larvae and in Crucifera. The effective compounds generally are stable and characterized by the active group R-S — in which the alkyl moiety must not be an allyl one. On the other hand, volatiles without sulphur, emitted by plants which do not belong to Cruciferae or Allium, do not stimulate the hymenopteran locomotor activity. These observations suggest that D. pulchellus is oligophagous, attracted to microlepidoptera developing on plants containing sulphur compounds and not only on Allium.

     

Charles de Gerville et les premiers restes de Plesiosauria signalés dans le Jurassique inférieur de France (Hettangien,région de Valognes,Manche)

The historian, archaeologist, and naturalist Charles de Gerville (1769–1853) reported as early as January 1816 the presence of fossil bones in the quarries of the region of Valognes, in the department of Manche. These quarries exploited the “Calcaire de Valognes” and the underlying “Argiles et Calcaires d’Huberville”, both formations dated as Lower Hettangian (Lower Jurassic). De Gerville communicated to Jacques-Louis-Marin Defrance a watercolour drawing of one of these fossil bones, discovered in July 1820, in which it is possible to recognize a plesiosaur femur. This femur, as well as a fragment of rib and three vertebrae of Plesiosauria from de Gerville's collection, was then figured in a publication by Arcisse de Caumont, in 1825. The plesiosaur femur was later acquired by Pierre Tesson of Caen, who owned one of the most important collections of fossils in Normandy. The Tesson collection was later purchased in 1857 by the British Museum (now The Natural History Museum, London), where the femur has been rediscovered. This specimen is the first known plesiosaur specimen ever discovered in the Lower Jurassic of France, before the genus Plesiosaurus was established upon material from the Lias of southwestern England. One of the vertebrae figured by de Caumont has been rediscovered in the “Muséum Emmanuel-Liais” (Cherbourg-en-Cotentin), which had acquired part of de Gerville's collection. The interpretation of the “fossil bones of Valognes” by Georges Cuvier, Henri Marie Ducrotay de Blainville, Arcisse de Caumont, Jacques-Amand Eudes-Deslongchamps and Constant Duméril is revealed through unpublished documents.