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  • Springer  (37,282)
  • Oxford University Press  (2,269)
  • 1970-1974  (38,114)
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  • 1972  (38,114)
  • 1946  (1,437)
  • 1
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The process of pigmentation of oil-droplets in the retina of three reptiles has been investigated with regard to ontogeny. — The ability of these animals to perceive colors was tested on different stages of life. Young Lacerta vivipara, with still uncolored oil-droplets., show optomotoric reactions to colors.
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  • 2
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    Zoomorphology 72 (1972), S. 331-340 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The larval eye of the deep-sea fish Cataetyx memorabilis differs from the eye of the adult in several morphological facts: Its position is lateral, the shape is circular, the diameter is 30% of the head's length. (In the adult: position of eyes is dorsal, shape of eye is oval and the main axis corresponds to 8.3 % of the head's length.) 2. Anatomically 9 different retinal layers can be distinguished in the larval eye, with the bipolar cell—and the ganglion cell layer being the widest ones. 3. Ultrastructural investigations revealed grouped photoreceptors, rod-shaped pigment granules and lipid bodies in the choroid. 4. Serial sections allowed the reconstruction of the path of the optic nerve from the anterior-ventral part of the eye to the anterior-lateral zone of the brain. 5. Despite the larval character of the absence of outer segments, the larval eye seems to be suited for life in the mesopelagial, for it shows the typical adaptations to vision in twilight zones, e.g. enlargement of eye, pupil and lens; ratio of photoreceptor- to bipolar- to ganglion cell bodies 100:20:20 (i.e. grouped photoreceptors); absence of large posterior chamber and presence of lipid particles in the choroid.
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  • 3
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé La structure décrite présente certainly des caractéristiques des sensilles olfactives classées dans la catégoric basiconica de Schneider et Steinbrecht (1968). Mais son étude ultrastructurale met en évidence plusieurs traits originaux. Seule la région apicale du pro cessus externe présente des perforations. L'épaisseur de la cuticule varie, de la base au sommet. Un épaississement cuticulaire situé sous la couronne perforée délimite deux chambers, dans lesquelles la perception olfactive pourrait se faire selon deux modalités. Le système dendritique largement ramifié semble avoir des rapports étroits avec le système pores-tubules périphériques. II s'agit d'un récepteur polyneuronique; le nombre des cellules sensorielles est élevé (supérieur à 30).
    Notes: Summary This new structure showed some of the caraeteristies of the basiconica olfactory senszlla — in the classification of Schneider and Steinbrecht (1968); but several original features appeared by electron microscopy study. The thickness of the cuticle is variable along the external process from the bottom to the tip: only the apical part bears ranges of pores; below (on 1 μ) the cuticle forms a thickening which defines two chambers; in each of them, it is possible that the olfactory perception is according to different modalities. The dendrites are branched and are certainly closed to the pore-tubules system. It is a polyneuronic receptor; the number of the sensory ells is upper than 30.
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  • 4
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    Zoomorphology 73 (1972), S. 45-61 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary From comparisons between bat wing structures and aerofoils and high-lift devices with known aerodynamic data, from the aeronautical literature, deductions are made regarding the function of some bat wing structures. Special arrangements in the hand wing add to rigidity and reduce the demands for powerful muscles and thick digits, thereby reducing the mass of the wing. 1. The anterior part of the wing, formed by the membrane parts anterior to the arm and third digit, is proportionally broad in megachiropteran bats as well as in many broad-winged microchiropteran bats. These parts can be lowered by the thumb and by pronation of the manus, and may together function as a leading edge flap. Leading edge flaps of aeroplanes permit, when lowered, higher angles of attack without separation, and thus higher lift coefficients. The leading edge in bats is very sharp, which increases the effectiveness of the leading edge flap. 2. The Reynolds number of bat wings lies in an interesting range, where the lift coefficient can be improved by induced turbulence of the boundary layer. The arm and digits, projecting markedly over the dorsal surface of the wing, and hair may function as turbulence generators. 3. The tension forces of the membrane on the digits have different effects upon the different digits, depending on the tautness of the surrounding membrane parts. The second digit and distal phalanx of the third digit are exposed mostly to bending in the membrane plane. The phalanges of the fourth and fifth digits are exposed to large dorsoventral bending. 4. Two arrangements add to relieving the distal part of the wing of large tension forces, thereby reducing the demand for a powerful extensor muscle of the distal phalanx (-ges) of the third digit: 1. The fourth and fifth digits act to alter the direction of tension. 2. By splitting the wing membrane in several parts by the digits, the second and third phalanges (the second in fruit-bats) of the third digit, which constitute the distal part of the wing's leading edge, are exposed to tension forces transformed from forces only from the nearest patagium. If the wing membrane would be outstretched only by one digit, as was the case in pterosaurs, the leading edge digit would have to resist the tension forces transformed from forces from the entire membrane posterior to the arm. 5. The fourth digit is angled in such a way that the proximal part of the membrane between the third and fourth digits is kept very taut, and the fourth metacarpophalangeal and interphalangeal joints are held very steady without any need of large muscular forces.
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  • 5
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This article deals with the gross and microscopic anatomy of the tongue and tongue region of the lower jaw of Gnathonemus petersii (Mormyriformes, Teleostei). The osteology coincides largely with that of Mormyrus caschive; the cranial muscles differ from those of most other fish through the absence of the m. intermandibularis posterior. The innervation of the tongue appears to be by the ramus palatinus superior n. facialis (VII). Microscopically the overall picture of the tongue is that of a deflated tube which consists at the outer portion of a compact continuous fibrous connective tissue surrounding an inner part which contains mainly loosely arranged collagen and reticular or elastic fibers with a few cells and little recognizable matrix. A comparison is made between the tongue structure of G. petersii and those of three other bony fish, Phoxinus phoxinus (Cyprinoidei), Plecoglossus altivelis (Salmonoidei) and Polypterus (Braehyopterygii).
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  • 6
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ultrastructure of a lateral organ in the head of Polyxenus lagurus which has been recently erroneously termed “cerebral gland” is described. It turned out to be a neurohaemal organ and not a gland, apparently homologous to the organ of Gabe of the luliformia.
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  • 7
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    Zoomorphology 71 (1972), S. 180-188 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hitherto essential features of the hip musculature of the orang-utan are still not known completely, although they are of special interest for phylogenetical considerations. As a first step to a more complete knowledge of the muscular system of this animal the author clarifies the homologies of the superficial gluteal musculature on the basis of new dissections. The findings reveal important viewpoints for discusion on the phylogenetical interconnections between the Hominoidea.
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  • 8
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    Zoomorphology 71 (1972), S. 299-327 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The muscle and skeleton anatomy of the pectoral, pelvic, and anal fins are described in 3 Salariin Blenniidae: Salarias fasciatus (sublittoral), Istiblennius edentulus (eulittoral), Alticus kirkii (supralittoral). In A. kirkii these organs are adapted to a climbing habit on the steep rocks beyond the water. The results are compared with those found in Periophthalmus.
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  • 9
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The neurosecretory cells (NSC) in the breeding phases show gigantic sized droplets. NSC show two peaks of activity in females at midnight and at 9 A.M., while a single peak occurs in males between midnight and 3 A.M. Light has a triggering effect on the neurosecretory release. The corpus cardiacum is the main neurohaemal organ. It has a nerve core formed by the nervi corpus cardiacum I and II, which is surrounded by the glandular region. Intrinsic secretory chromophilic cells and chromophobic cells occur randomly. Aorta is probably not a storage-release centre. The corpora allata are lobulated structures, showing cyclical activity which is correlated with egg-maturation. No neurosecretory material occurs in allatum.
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  • 10
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    Zoomorphology 72 (1972), S. 131-172 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The jaws of the family Gnathostomulidae have four major parts (fig. 80) : articularium, involucrum, dentarium, and suspensorium. 2. The articularium is highly specialized and fully freed from functions other than articulation of the jaws and the prevention of twisting motions. It consists of a symphysis lamella, joined by a symphysis in vertical position. 3. The involucrum is a specialization in the higher families of the Scleroperalia and the Austrognathiidae. In Gnathostomulidae it is of medium length with a well-defined caudal end, surrounding an apertura caudalis. From there a much thinner tectum lateralis continues. It is formed by a dorsal extension of the lamella interna which bends-as lamella externa-laterally and then ventrally, leaving only a fissure-like opening medioventrally: the incisura ventralis. 4. The dentarium consists of a thin lamella interna, which is always thickened in three portions, forming the arcus dorsalis, medialis, and ventralis. These arcs form the bases of the teeth. The arcus medialis also bears the strong dens terminalis. The dentation is more complicated and minute than the light microscope can resolve. An incisura dorsalis is found in few cases, cutting into the lamella interna from the caudal end. 5. The suspensorium is specialized into two portions: an anchorage part at the more fixed end., and an apophysis part nearer the moving ends of the jaw system. a) The cuticularized parts of the cauda system are always paired, but can be symmetrically or asymmetrically developed. In the first case the cuticularized caudae are tube- or cushion-like; in the latter case they are tubeshaped again, but a cauda dorsalis and a cauda ventralis can be distinguished. b) The apophyses are wing-shaped only distally, proximally they are differentiated (fibularized) into two fibulae functioning as cuticularized sinews: the fibula medialis originates at the ventrocaudal end of the lamella interna, the fibula lateralis at the ventral margin of the lamella externa. Together they form the fenestra ventralis, varying in dimension. c) In addition a fibula radialis is developed, strengthening the apertura caudalis of the involucrum. This fibula originates at the connecting point of the ventrocaudal end of the lamella externa and the fibula lateralis and it inserts in the caudal portion of the lamella interna either ventrally or dorsally. In the latter case it seems to be replaced by a sinew. Corresponding to its position it may bisect the fenestra ventralis into a fenester ventrocaudalis and ventrofrontalis and/or the apertura caudalis into a apertura caudolateralis and caudomedialis. 6. The basal plate is composed of three major parts: pars centralis, pars alaris, and the serrula. 7. The pars centralis forms a roof-like structure originating on the basis denticis, on top of the transverse axis, or the dorsum alae, of the wing system. A strong dens medialis forms the ridge of the roof, while groups of teeth form the margins. 8. The pars alaris consists of a dorsum alae—the stronger middle part, stretched in transverse direction. On both ends it bifurcates, thus forming five separate areas within the pars alaris: two are paired-the alae frontales and the alae laterales—and the unpaired mediocaudal portion, the tectum caudalis, which is much thinner. These portions seem to correspond to the widely representative five-partition of the alae in basal plates of Gnathostomulida. 9. The distal portion of the frontomedial margin of the alae frontales always bears a flat, scale-like dentation: the serrulae. Only in the genus Gnatliostomula does the proximal portion of this margin not end freely; it bends medially underneath the pars centralis. There the two sides meet and form an infundibulum. In this construction the originally paired serrulae continue proximally and fuse medially on the infundibulum.
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  • 11
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    Zoomorphology 72 (1972), S. 173-202 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfawung Mit vorliegender Untersuchung wird der bisher unklare Mechanismus der Autotomie bei Spinnen (Araneae) geklärt. Als Objekte wurden Vertreter aus den Familien Philodromidae, Lycosidae and Agelenidae verwendet. Die Autotomie erfolgt bei diesen Spinnengruppen stets an einer bei alien Laufbeinen vorhandenen präformierten Stelle zwischen Coxa and Trochanter. Ein direkt proportionaler Zusammenhang zwischen der relativen Länge der Extremitäten und der Häufigkeit ihrer Amputation lieβ sich finden. Die Autotomie erfolgte im Versuch bei Quetschung der proximalen Beinglieder, beginnend im allgemeinen ab Tibia. Das gilt fur alle Laufbeine. Reizeinwirkung leitet die Autotomie ein, indem Coxa, Trochanter and Femur eine besondere Lage zueinander einnehmen, so daß sich die Interartikularhaut zwischen Coxa and Trochanter dorsal median spannt. Wird der Reiz fiber ein fur das Tier erträgliches MaB hinaus gesteigert, so zuckt die Coxa jäh nach oben, wahrend das Femur durch seine relative Unbeweglichkeit als Widerlager fungiert. Der zwischen beiden liegende Trochanter maß deshalb durch entsprechende Drehbewegung zwischen der Dynamik der Coxa and der Statik des Femur ausgleichen, indem er sich dorsal weiter von der Hüfte wegbewegt und so eine Kraft erzeugt, die sich voll auf die Gelenkhaut zwischen Coxa and Trochanter auswirkt and ihre dorsal median beginnende Ablosung vom Trochanter zur Folge hat. Die besonderen anatomischen Verhältnisse bedingen, daß these ,zerreiβende Kraft" 50% gröβer als die aufgewendete Kraft der Coxa ist. Sie wirkt zuerst auf einen Sklerit (Nr. II) ein, mit dem die dorsale mediane Gelenkhaut auf dem, proximalen Trochanterrand verwachsen ist. Unterstützt wird die Amputation durch eine wirkungsvolle and rasche Abstandsvergrößerung zwischen dem. oberen Coxa- and Trochanterrand, da besonders diejenige Kreisbahn, die der dorsale proximale Trochanterrand beschreibt, eine starke Krümmung auf-weist. Der geschilderte Bewegungsablauf wahrend der Autotomie war bei den untersuchten Objekten der genannten Familien gleich. Bei Pardosa und Tegenaria überträgt eine zusätzliche Bildung, der schräg verlaufende Sklerit Nr. IIIa, einen Teil der von der Hüfte erzeugten zerreißenden Kraft direkt and konzentriert auf den Ort der beginnenden Autotomie. Der Zug eines Angreifers an einem Bein und der Gegenzug der Spinne spielen keine ausschlaggebende Rolle. Die Amputation beginnt mit der Ablosung des Sklerits Nr. II von seiner Verwachsungsstelle mit dem Trochanter; da aber gerade an ihm keine Muskeln ansetzen, kann die direkte Beteiligung der Hüftmuskulatur verneint werden. Der Amputationsort wird nur von einem Muskel gequert, der sich äuBerst leicht von seiner Insertion im Trochanter lost, wahrend die restlichen 7 Muskeln sämtlich an den verdickten Gelenkhauträndern angreifen. Die Verwachsungsstellen der Sklerite mit dem Trochanter sind weniger zugbelastungsfähig als die Verbindung der Muskeln mit den betreffenden Skleriten. Diese indirekte Wirkung der Muskeln auf den Trochanter deutet ebenfalls auf die Tatsache hin, daβ es sich bei dem Amputationsort um eine präformierte Stelle handelt. Wegen der geringen Wahrscheinlichkeit der Verletzung eines Pedipalpus ist die Fähigkeit zur Amputation dieser verkürzten Laufbeine bei Pardosa und Tegenaria verschwunden; außerdem liegt die schwächste Stelle dieser Gliedmaßen zwischen Trochanter and Femur. Bei Philodromus ist wegen des laterigraden Typus die Möglichkeit der Verletzung zu 1 % noch gegeben. Aus diesem Grund dürfte sich hier die Fähigkeit zur Autotomie zwischen Coxa and Trochanter erhalten haben. Sowohl bei Philodromus als auch bei Pardosa and Tegenaria fand sich — jedoch nur an der Amputationsstelle der Laufbeine — ein ausgezeichnet funktionierender Wundverschluβ: Sklerit Nr. I and III werden dabei durch Muskelzug und Druck der Hamolymphe „wie die beiden Klappen eines Hausmüllschluckers” aufeinander zubewegt and die Wunde geschlossen. Dieser Mechanismus, Bowie ihr Vermögen einer Kompensation verlorengegangener Beine durch geschickte Verwendung der verbliebenen, beweist ebenfalls die vollendete Anpassung der Spinnen an den Verlust der Gliedmaβen.
    Notes: Summary With the present study, the previously unknown mechanism of autotomy in spiders is clarified. Specimens of the families Philodromidae, Lycosidae and Agelenidae were used as subjects. In those groups of spiders, autotomy always occurs at a preformed place between coxa and trochanter, a spot found at each leg. A directly proportional relation between the length of the extremities and the frequency of their amputation was to be found. In the experiment autotomy occured when the proximal parts of the leg, generally beginning from tibia, were squeezed. This is true for all legs. Irritation starts autotomy, with coxa, trochanter and femur taking up a particular position, so that the articular membrane between coxa and trochanter tightens at its dorsal median part. If the animal is exposed to a stimulus greater than it can bear, the coxa jerks abruptly upward, while the femur, by its relative immobility, functions as an abutment. Therefore the trochanter, lying between them, has to balance the movement of the coxa with the static quality of the femur by moving its upper part away from the coxa, thus producing a power which takes full effect on the articular membrane between coxa and trochanter, and entails its amputation from trochanter, beginning at its dorsal median part. Because of the particular anatomical conditions, this “breaking power” is 50 % greater than the one produced by the coxa. It first works on a sclerite (No. II), with which the dorsal median articular membrane is connected on the proximal rim of trochanter. Autotomy is favoured by an effective and rapid increase of the distance between the upper edge of coxa and trochanter, especially as the circular line described by the dorsal proximal edge of trochanter is considerably curved. The described process of autotomy was the same in each detail with every examined specimen of the above-mentioned families. In Pardosa and Tegenaria the additional oblique sclerite Ills, transfers part of the breaking power, produced by coxa, directly and fully to the place where autotomy begins. The pull of an aggressor at one leg and the counter-pull of the spider do not play a decisive part. The amputation is started by detachment of sclerite No. II from its place of connection with trochanter; but as there are no muscles inserted, a direct participation of the muscles of coxa is not involved. The place of amputation is traversed by one muscle only, which detaches itself from its insertion in trochanter very easily, while the remaining seven muscles are all inserted in the thickened rims of the articular membrane. The places where the sclerites are connected with trochanter are less capable of bearing tensile stress than the connection of the muscles with the respective sclerites. The indirect effect of the muscles on trochanter also points to the fact that the place of amputation is preformed. As a pedipalp is not very likely to be injured, the capability of amputation of those extremities is no longer to be found in Pardosa and Tegenaria; moreover, those extremities have their frailest point between trochanter and femur. In Philodromus there is still a 1 % probability of being hurt because of the laterigrade type. For this reason, the capability of autotomy between coxa and trochanter might have been preserved here. In Philodromus as well as in Pardosa and Tegenaria there was an excellent working mechanism for the closing of wounds, however, only at the place of amputation of the legs: sclerite No. I and III are moved towards each other “like the two flaps of a waste-disposer”, and thus the wound is closed. This mechanism, as well as the spiders' capability of compensating lost legs by skilfully making use of the remaining ones, proves their accomplished adaption to the loss of extremities.
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  • 12
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    Zoomorphology 72 (1972), S. 77-130 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung 1. Da die Klassifizierung der Zapfentypen aufgrund von morphologischen Merkmalen schwierig ist, werden: a) die Entfernung der Zapfenellipsoide von der Membrana limitans externa; b) die Stellung der Zapfen innerhalb des Mosaiks als weitere Kriterien herangezogen. 2. Die Doppelzapfen konnen in parallelen Reihen stehen (Reihenmuster) oder im Quadrat angeordnet sein (Quadrat- oder Rechteckmuster). In beiden Mustern können zu den Doppelzapfen em. oder zwei Einzelzapfentypen hinzutreten. 3. Die beiden Mustertypen stehen in einem ontogenetischen Zusammenhang: An der Ora serrata werden alle Doppelzapfen in parallelen Reihen angelegt and erst im Retinainneren bei den entsprechenden Arten zu Rechtecken umgeordnet. 4. Bei Betta and Nannacara stehen innerhalb des Doppelzapfenquadrats jeweils vier Stäbchen; bei einigen anderen Arten umgeben bis zu acht Stabchen kranzartig die Einzelzapfen. In den moisten Fällen sind die Stäbchen zahlreicher als die Zapfen. 5. Wahrscheinlich besteht ein Zusammenhang zwischen Augendurchmesser bzw. Alter and der regelmäßigen Anordnung Bowie der Zahl der Stäbchen. 6. Es werden verschiedene morphologische Zelltypen der drei Horizontalenreihen beschrieben and ihr Vorkommen bei bisher von anderen Autoren (besonders Cajal) untersuchten Arten erörtert. 7. Aufgrund von morphologischen Merkmalen kann nicht entschieden werden, ob die Horizontalen Neuronen oder Glia-Elemente sind. 8. Die Reihen der scleraden Horizontalen verlaufen — unabhängig vom Typ des Doppelzapfenmosaiks — parallel zu den Einzelzapfenreihen. 9. Die Einzelzapfenabstände and die Entfernung zwischen den Kernen der äußeren Horizontalen sind gleich groß. 10. Die mittleren and inneren Horizontalen sind nur dann regelmäßig angeordnet, wenn sie aus lappig-sternförmigen Zellen bestehen. 11. Bei Rechteck- und Streifenmustern ist die Anzahl der Horizontalenschichten ebenso groß wie die der Zapfentypen. 12. Die relativen Zahlenverhältnisse von Doppelzapfen zu Einzelzapfentypen bzw. äußeren zu mittleren and inneren Horizontalen zeigen bei vielen Arten eine gute Übereinstimmung. In absoluten Zahlen ausgedrückt kommen auf jede Horizontale 2 Zapfen. Nur die inneren Horizontalen weichen bei einigen Arten von dieser Regel ab. 13. Beim Vergleich verschiedener Rechteckmuster ergibt sich ein zahlenmäßiger Zusammenhang zwischen mittleren Horizontalen and zentralen Einzelzapfen, vitreaden Horizontalen and eckständigen Einzelzapfen Bowie scleraden Horizontalen und Doppelzapfen. 14. Die Beziehung zwischen der Anzahl der Zapfentypen and der Anzahl der Horizontalenreihen Bowie deren Bedeutung fur das Farbensehen wird durch elektrophysiologische Befunde von Svaetichin bestätigt. 15. Es werden Funktionsmodelle des Bewegungssehens and der lateralen Inhibition aufgrund der Lagebeziehung zwischen Zapfen- und Horizontalenmuster diskutiert. Experimentelle Befunde zu diesen Modellen liegen bisher nicht vor.
    Notes: Summary 1. Since the classification of the cone types on morphological features is difficult a) the distance of the cone-inner-segment from the outer limiting membrane b) the position of the cones within the mosaic are used as further criteria. 2. The double cones are either arranged in parallel rows (row-mosaic) or in square units (square mosaic). In both types one or two single cones may be added to the basic pattern. 3. There is an ontogenetic relation between the two mosaic types: Near the Ora serrata, all double cones are placed in parallel rows and only in the more central part of the bulbus of certain species are they arranged in squares. 4. In Bettta and Nannacara 4 rods are enclosed in every square unit; in some other species there are up to 8 rods surrounding the single cones. In most cases rods are more numerous than cones. 5. Probably there is a relationship between the age and diameter of the eye and the regular arrangement resp. the number of the rods. 6. The different morphological types within the three layers of horizontal cells are described. Their occurence and distribution is compared to the findings of other authors (chiefly Cajal). 7. Based on morphological characteristics one cannot determine whether the horizontal cells are neurons or glia elements. 8. The rows of the sclerad horizontal cells run parallel to the rows of single cones without respect to the type of double cone mosaic. 9. There is an equal distance between the nuclei of the single cones and between the nuclei of the outer horizontal cells. 10. The middle and inner horizontal cells are arranged regularly only when they consist of lobed stellar shaped cells. 11. In square and row mosaics the number of horizontal cell layers equals the number of cone types. 12. The relative ratio of double cones to single cones is in good agreement with that of sclerad to intermediary and vitread horizontal cells. In absolute figures there are 2 cones for every horizontal cell. Only the vitread horizontal cells of a few species do not fit this rule. 13. If one compares different square mosaics, one finds a quantitative relation between intermediary horizontal cells and accessory single cones as well as between sclerad horizontal cells and double cones. 14. The correlation between the number of cone types and the number of horizontal cell layers and its functional significance for colour vision is confirmed by the electrophysiological data of Svaetichin. 15. Several functional models of movement perception and lateral inhibition are discussed on the basis of a parallel arrangement of the cone—and the horizontal cell mosaic. Until now there are no experimental data confirming these models.
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  • 13
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Bei einigen Spinnen, vor allem aus der Familie der Araneidae, bilden funktionell umgewandelte Mitteldarmzellen unmittelbar unter der Hypodermic eine nahezu geschlossene Zellschicht, die mehr oder minder stark mit Guaninkristallen angefiillt sein kann. Die distalen Zellbereiche dieser von uns als Guanocyten bezeichneten Zellen verzahnen rich mit der Hypodermis selbst oder stehen mit dem schmalen hypodermalen Hämolymphsinus in Verbindung. Thre proximalen Enden sind lang ausgezogen und schieben sich zwischen nicht umgewandelte Resorptionszellen. Jede Guanocyte steht mit dem Mitteldarmlumen in direkter Verbindung. Auf Grund des Organellenbestandes sind die Guanocyten als spezialisierte Mitteldarmzellen auzusprechen, die während der reproduktiven Periode die übrigen exkretorisch tätigen Gewebe bzw. Organe unterstützen oder ergänzen, indem sie der Hämolymphe, der Hypodermis und den benachbarten Resorptionszellen pinocytotisch purinhaltige Abbauprodukte und andere Exkrete entnehmen. Dieselben werden unter Mitwirkung eines glatten endoplasmatischen Retikulums umgebaut und temporär intrazellulär als kompliziert aufgebaute Kristalle innerhalb von membranösen Kristallsäckehen gespeichert. Die Notwendigkeit intrazellulärer Exkretspeicherung auf Grund der Ernährungs-physiologie und Abwandlungen in der Funktionsmorphologie sowie fortschreitender Alterungserscheinungen wird diskutiert.
    Notes: Summary Guanocytes are present in several spiders especially of the family Araneidae. The guanocytes form a compact cell-layer under the hypodermis. Their distal parts remain connected to the hypodermic hemolymph sinus, while the proximal ends establish contact with the midgut lumen in the shape of a long cellular process. The organelle equipment of the guanocytes shows that they are specialized midgut cells. They support or replace the other excretory tissues and organs especially during the reproduction period. By pinocytosis, the guanocytes remove catabolites of the purine and protein metabolism from the hemolymph, the adjacent resorption cells of the midgut, as well as from the overlying hypodermis cells. The stored catabolites are formed into complex crystals assisted by the smooth endoplasmic reticulum. The necessity of the temporary intracellular excretory storage on the basis of the physiology of nutrition, changes in the functional morphology, and general signs of old age are discussed.
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    Zoomorphology 71 (1972), S. 203-289 
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    Notes: Abstract Four populations of Mesostoma lingua from various geographical areas react in different ways according to certain environmental factors. The determination of the two eggtypes is particularly influenced by temperature changes and a crowding effect. The influence of other factors is of little consequence.
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    Zoomorphology 71 (1972), S. 340-354 
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    Notes: Abstract Differences in the morphology of antennae (especially sensillae) and compound eyes (number of ommatidia) of both sexes are described.
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    Zoomorphology 72 (1972), S. 36-45 
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    Notes: Summary Covariational patterns of characters were compared in adults of two species of flies (Drosophila melanogaster and Musca domestica). Fourteen characters, homologous in the two organisms, were measured for both sexes in several laboratory strains of both species. Multiple factor analysis with rotation to an oblique simple structure was used to resolve the covariation into simpler patterns. Factor analyses were based on both the pooled within-group covariation as well as on total variation in each species. The five factors extracted from the correlation matrices of both species were quite similar after rotation (this was especially true for the within-group covariation). The following factors could be identified: a wing and a leg size factor, intercorrelated in the two species; a wing and thorax size factor; and separate factors affecting numbers of aristal and sternal setae. The present study is an example of the use of multiple factor analysis in comparative morphometrics
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    Zoomorphology 72 (1972), S. 203-230 
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    Description / Table of Contents: Zusammentassung Die Integumente der Priapuliden Halicryptus spinulosus und Priapulus caudatus sind ähnlich aufgebaut. Die miteinander verzahnten und über lange septierte Desmosomen verbundenen Epithelzellen tragen apikal eine amorphe, in Abhgngigkeit von der Häutungsphase± geschichtete Kutikula. Ähnliche Kutikulastrukturen finden sich bei Nematoden. Der Panzer der Halicryptus-Larve ist in seiner Ultrastruktur deutlich verschieden von der Kutikula adulter Tiere and zeigt auch keine Übereinstimmung mit dem Panzer der Kinorhynchen. Die epithelialen Stacheln der Art Halicryptus spinulosus enthalten mehrere Sekretzelltypen. Die epithelialen Differenzierungen am Rumpfende von Priapulus caudatus sind durch ihre Ultrastruktur ebenfalls als sezernierende Zellkomplexe gekennzeichnet. Der Feinbau des distalen Anhangsorganes von Priapulus caudatus entspricht der Ultrastruktur von Zellen mit aktivem Ionentransport. AuBerdem ist dieses Organ Träger von Mechanorezeptoren.
    Notes: Summary The integuments of the priapulids Halicryptus spinulosus and Priapulus caudatus exhibit a similar ultrastructure. The epithelial cells, the neighbouring lateral plasma membranes of which are frequently highly interdigitated, are connected by long septate desmosomes and are apically covered by an amorphous cuticle. The latter shows a stratification, the pattern of which is dependent on the moulting phase. Similar cuticular structures are to be found in nematodes. The cuticle of the larvae of Halicryptus differs markedly from that of the adult animals and also does not show agreements with the armour of kinorhynchs. It is threelaminated and contains in the middle layer canalicular structures. The epithelial spines of Halicryptus spinulosus contain various types of secretory cells. The epithelial differentiations at the end of the body of Priapulus caudatus also represent, according to their ultrastructure, secretory cells. The fine structure of the appendicular organs of Priapulus caudatus corresponds to that of cells engaged in ion transport. In addition this organ possesses mechanoreceptors. Both priapulids carry, on the integumental papillae and within the epithelium of the body and pharynx, characteristically constructed receptors with an apical cilium surrounded by seven microvilli. They are interpreted to represent mechanoreceptors.
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    Zoomorphology 72 (1972), S. 295-306 
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    Description / Table of Contents: Zusammenfassung 1. Die Vertreter der Gattungen Ligia, Oniscus, Porcellio und Cylisticus besitzen in jedem Thoraxsegment Muskeln mit transgredienten Anteilen. 2. Bei Armadillidium treten in den meisten Segmenten nur segmentale Muskeln auf. In bestimmten Segmenten ist ein Musket reduziert. 3. Mehrere Beobachtungen an Armadillidium zeigen jedoch, daß auch bei diesem Genus transgrediente Muskelübergänge fakultativ auftreten können. Diese Beobachtungen erlauben neben anderen Argumenten, wie z. B. der Lage eines Streckrezeptors, eine Homologisierung der vier median gelegenen Muskeln. 4. Eine Homologisierung der lateral gelegenen Muskeln ist nur indirekt mög-lich. Das VII. Segment liefert hierfür wertvolle Grundlagen. 5. Ergänzende mikroskopische Untersuchungen an Campecopea hirsuta (Sphaeromatidae) weisen darauf hin, daß die segmentale Aufgliederung der Muskelzüge Bsowie die Reduktion des M. d. segm. lateralis eine Anpassung an das verbesserte Kugelungsvermögen darstellen.
    Notes: Summary 1. Representatives of the genera Ligia, Oniscus, Porcellio and Cylisticus possess dorsal muscles with transgredient parts in each thoracal segment. 2. In most segments of Armadillidium spp. there occur only segmental muscles without visible transgredient portions. The number of muscles is reduced. 3. In some segments transgredient portions of longitudinal muscles may occur even in Armadillidium. Their occurrence, amongst other arguments, permits the homologisation of the four median muscles. 4. Homologisation of the two lateral muscles of Armadillidium is speculative and is mainly based on the arrangement of the muscles in the VIIth segment. 5. Additional observations on Campecopea hirsuta, a sphaeromatid isopod, further strengthen the assumption that the segmental arrangement of the dorsal muscles as well as the reduction of the M. dorsalis segmentalis lateralis is an adaption to the increased ability of volvation in these genera.
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    Zoomorphology 72 (1972), S. 307-330 
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    Notes: Summary The development of cells of the olfactory organ in young (parr and smolt) and adult Baltic sea trout is investigated from an ecological point of view. A theory on cell dynamics is presented. Blastema cells are basal cells which divide into goblet cells, primary receptors and primary supporting cells. The latter cell type reminds one of undifferentiated fibroblasts. In the indifferent epithelium the primary supporting cells then differentiate into ciliated nonsensory cells, whereas in the sensory epithelium they form ciliated and nonciliated supporting cells. The primary receptors develop into spindle receptors, and these into rod receptors. This dimorphism of supporting cells and receptors and the grouping of them is discussed. Indications on aging of the epithelium are presented. The epithelial cells are arranged in zones. Mainly in the basal zone there is a supply of lymphoid wandering cells and macrophages some of which move into other zones and phagocytize dead or degenerating cells. Dead cells are also extruded into the olfactory chamber. This occurs especially during the initial secondary folding of the primary olfactory laminae. Different aspects on ecological adaptation of cells and structures are presented. Baltic sea trout have a dynamic cell population and secretion adapted for life both in river and sea.
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    Zoomorphology 72 (1972), S. 341-348 
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    Description / Table of Contents: Zusammenfassung Bei einer südafrikanischen Art der Gattung Caenesteriella wird der Bau des zungenförmigen Labrum beschrieben. Im Inneren des Labrum liegen Drüsen von verschiedenem Ban (Typ A and B). Die unpaare mediane and ein Paar seitlicher Drusen vom Typ A Bind kompakt. Sic bilden ein Syncytium mit zahlreichen großen, z.T. verzweigten Kernen. In jeder Drüse führt ein cuticularisierter Ausführgang von einer großen Sammelblase nach außen. Mehr basal liegen ein Paar Drüsen vom Typ B, die stärker aufgegliedert Bind. Die Kerne sind kleiner und nicht verzweigt. Sammelblasen fehlen, die dünnen Ausführungsgänge münden getrennt. Seitlich im Kopf liegt ein weiteres Paar Drüsen vom Typ B. Es steht nicht im Zusammenhang mit den labralen Drüsen. Die Ergebnisse werden besonders mit den Angaben Sterbas (1957) an Daphnia verglichen.
    Notes: Summary In a Southafrican species of Caenesteriella the tongue-like labrum is described. Inside the labrum there are two types of glands (A and B). Three glands of type A are compact, forming a syncytium with numerous large and often ramified nuclei. From each gland a cuticular duct has its source. At the base there is one pair of glands, belonging to type B. These glands are diffuse. The nuclei are small and not ramified. There are no reservoirs, but two ducts. At both sides of the head there are two more glands of type B. There is no connection with the labral glands.
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    Zoomorphology 73 (1972), S. 63-79 
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    Description / Table of Contents: Zusammenfassung 1. Der in Mittel- und Südamerika weit verbreitete Kiemenschlitzaal Synbranchus marmoratus wird mit seinem in Höhlen Yucatans lebenden augen- und pigmentreduzierten Derivat Furmastix infernalis unter besonderer Berücksichtigung der Sinnesorgane verglichen. 2. Der Bau von Nase und Kopfkanalsystem ergibt keine Unterschiede. Allein die Zahl der freien Neuromasten und der Geschmacksorgane ist bei F. infernalis erhöht. 3. Abgesehen von der Schwanzlänge ergeben sich in den meristischen Daten keine Unterschiede. Die weitgehend auf der Augen- und Pigmentreduktion der Höhlenform basierende generische und artliche Trennung wird daher in Frage gestellt. 4. Der Reduktionsgrad der Augen und des Melaninpigmentes des F. infernalis läßt diesen im Vergleich zum troglobionten mexikanischen Characiden Astyanax (=Anoptichthys) mexicanus als phylogenetiseh jüngeren Höhlenfisch erscheinen. Dieser Befund wird durch geologische Daten gestützt.
    Notes: Summary 1. The synbranchide Synbranchus marmoratus, which is widespread in Middle and South America, is compared with its eye- and pigment-reduced Yucatan cave derivative Furmastix infernalis with special reference to the sense organs. 2. The structure of noses and cephalic lateral line systems of both forms is not different. The number of free neuromasts and taste buds is enhanced in F. infernalis. 3. Apart from a prolonged tail in the cave fish there are no differences concerning meristic features. Therefore generic and specific distinction between the two forms, which is mainly based on the reduction of eyes and pigment of the hypogean fish, is made uncertain. 4. Eyes and pigment of F. infernalis are less reduced than in Astyanax (Anopt-ichthys) mexicanus (Charaeidae, Pisces). Thus F. infernalis is presumably the phylogenetically younger cave fish. This result is supported by geological dates.
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    Zoomorphology 73 (1972), S. 117-144 
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    Description / Table of Contents: Résumé 1. La régénération de la région antérieure de Phoronis psammophila se produit après autotomie ou amputation (après section transversale an niveau de la zone d'autotomie dans ce travail). Le lophophore rejeté ou sectioneé est incapable de régénérer et dégénère. 2. La régénération se déroule selon 8 stades successifs (en 3 jours environ). Les trois premiers stades portent sur la cicatrisation, avec bouchon cicatriciel, et sur la formation du blastème de régénération. Les stades suivants correspondent aux diverses étapes de l'organogenèse. 3. L'organogenèse concerne principalement le tube digestif (avec formation d'un stomodeum, mais pas de proctodeum), l'appareil circulatoire lophophoral, les néphridies, les mésentères, le lophophore et les tentacules, l'épistome. 4. La régénération de la région antérieure des Phoronidiens est un phénomène physiologique, habituel et fréquent; son déroulement normal est très rapide.
    Notes: Summary The regeneration of the anterior body part in Phoronis psammophila, sectioned transversaly near the autotomy line, is divided into 8 periods: the first 3 on wound-healing and regenerating blastem, the others on organogenesis. The development of the regenerate is described in detail, especially the digestive tract, the lophophoral circulatory system, the nephridia, the mesenteries, the lophophore, the epistome.
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    Zoomorphology 73 (1972), S. 249-261 
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    Description / Table of Contents: Zusammenfassung 1. Es wurden 54 Psocopteren-, 108 Amblyceren- und 263 Ischnocerenprdparate ( die der Trichodectiden eingeschlossen) untersucht, um Wege zur Unterscheidung und zum Vergleich der verschiedenen Formen des typischen Hypopharynxskelettes der Psocodea zu finden. 2. Mit Hilfe der am Hypopharynx anzutreffenden Muskelinsertionen konnte ein Weg zur Homologisierung der Sitophorelemente der Psocodea mit den Teilen des Hypopharynxskelettes von primitives Apterygoten (Grundplan nach Gouin, 1968; Matsuda, 1965) aufgezeigt werden. 3. Das Cibarialsklerit eines Teils der Psocoptera weist eine Reihe von Gemeinsamkeiten mit denen prototypischer Amblycera und Ischnocera auf. Das der Trichodectiden unterscheidet sich davon und ist möglicherweise Ausdruck einer seit langem eigenständigen Entwicklung. 4. Da zwischen den Skleriten verschiedener Gattungen und auch höherer Einheiten charakteristische Unterschiede bestchen, scheint es möglich, these zur Überprüfung systematischer Einheiten heranzuziehen. Dazu sind weitere Untersuchungen nötig. 5. Die Auswertung der bei den Trichodectidae bisher vorgefundenen Merkmale scheint darauf hinzudeuten, daß die Überfamilie Trichodectoidea Burm. aus der Unterordnung Ischnocera herauszunehmen und als eigene Unterordnung zu führen ist. Grundlage dieser Auffassung ist neben der spezifischen Sitophorform die charakteristische Muskelversorgung des Epipharynx und eine Reihe weiterer Merkmale (vgl. Königsmann, 1960).
    Notes: Summary 1. 54 specimens of Psocoptera, 108 specimens of Amblycera and 263 of Ischnocera babe been examined to compare the hypopharyngeal skeletons (sitophor — Snodgrass, 1944). 2. As a result a procedure for homologizing the elements of Psocodean sitophor with those of primitive Apterygotes (Gouin, 1968; Matsuda, 1965) was established. 3. The sitophor of Psocoptera in more or less similar to that of Amblycera and Ischnocera, but it is prototypical in Trichodectidae. 4. Consequently it is necessary to separate Trichodectidae from Ischnocera. A comparison of muscle attachments is Trichodectidae (Risler, 1951) and other Ischnocera (Haub, 1971; Symmons, 1952) corroborates these findings. 5. An appointment of generic value seems to be possible. Nevertheless the degree of systematic significance must still be stated for other families, genera and species.
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    Wood science and technology 6 (1972), S. 165-184 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The membranes of bordered pits were investigated in 120 species of 47 genera of the gymnospermous families, using light and electron microscopic techniques. A great variability in the morphological structure of the pit membranes has been established. The differences in structure are pronounced and depend mainly on the genus involved. A classification of six morphological “structure types” is presented. They do not necessarily correspond with the chemical composition and the functional behaviour. The results on the variability of the pit membrane have shown the necessity of an extended definition for the torus.
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    Wood science and technology 6 (1972), S. 196-203 
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    Notes: Summary The newly matured intervessel pit membranes of yellow poplar contain distinct openings. With increasing age the membranes become progressively occluded with incrustations which obstruct the small openings. Openings were not detected in the vessel-to-ray parenchyma and vessel-to-fiber pit membranes at any age.
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    Wood science and technology 6 (1972), S. 215-229 
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    Notes: Summary Terms used in relation to swelling pressure are first defined. The present status of knowledge of the swelling pressure of wood under various conditions is then briefly discussed. Methods are outlined for the determination of swelling pressure with restraint in one direction only and their limitations discussed. The method developed by Tarkow and Turner for the determination of swelling pressure when restraint is present in two directions is also referred to and outlined. Conclusions are then drawn from the present status of knowledge of swelling pressure in wood and gaps in this knowledge are indicated.
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    Wood science and technology 6 (1972), S. 239-248 
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    Notes: Summary Particle boards are of increasing economic importance. Without special treatment they are destroyed by termites. Deterioration of unprotected material as well as possibilities and present knowledge of preservation against termite attack are briefly described. Recent laboratory experiments with particle board treated to make it resistant to humidity and basidiomycete fungi showed that only one organic preservative out of four protected the boards also against termite attack; one of two water-soluble preservatives gave promising results. Heterotermes indicola (Wasmann) from India proved to be more aggressive and resistant to the preservatives than Coptotermes amanii (Sjöstedt) from Kenya and Nasutitermes nigriceps (Haldemann) from Guatemala. Kalotermes flavicollis (Fabr.) from Italy was also very tolerant to the fungicidal preservatives. Further development of treatments of particle board against termites is required.
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    Wood science and technology 6 (1972), S. 67-77 
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    Notes: Summary Dielectric measurements were carried out on moist wood at 25° C in a.c. fields from about 4...500 rms V/cm and over a frequency range from 100 Hz...100 kHz. During the measurements the wood specimens were hermetically sealed in a special type of sample holder. With this new measurement technique it was found that the dissipation factor and dielectric conductivity were field-dependent at low frequencies.
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    Wood science and technology 6 (1972), S. 59-66 
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    Notes: Summary Oven dried basswood was vacuum impregnated with methyl methacrylate monomer containing various amounts of free radical catalyst and trifunctional crosslinking agent. The wood-monomer composite was polymerized at 60°C in an air oven and the rate of heat generated was followed by means of a thermocouple placed in the center of the sample. Increasing the concentration of Vazo free radical catalyst in the basswood-MMA impregnated samples reduces the time to the exothermic peak and increases the exothermic peak temperature. High Vazo concentrations also decraase the percentage conversion of monomer to polymer. Trimethyl propane trimethacrylate (TMPTMA) crosslinker reduces the time to the exothermic peak and dramatically increases the exothermic peak temperature. The use of a crosslinker rapidly increases the initial viscosity of the system, and therefore, the autoacceleration of the polymerization is more pronounced.
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    Wood science and technology 6 (1972), S. 85-94 
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    Notes: Summary One of the problem areas in the kiln drying of western hemlock lumber is the wide variation in final moisture content of the wood. This variation in moisture content is due to the presence of sinker or wetwood in the heartwood. The features of wetwood which differentiate it from the normal heartwood include higher specific gravity, higher extractives content, and lower permeability. The apparent higher specific gravity can be fully accounted for by the higher extractives content. The principial extractive is α-conidendrin. The wetwood in western hemlock often occurs together with ring shake and under these circumstances the white deposit on the shake surfaces is also α-conidendrin and not matairesinol, the substance usually associated with ring shake in western hemlock. A viewpoint is presented on the origin of wetwood as the endproduct of a reaction by the tree to injury, i.e., ring shake, in which additional extractives are deposited. The extractives result in a greatly lowered permeability, which prevents loss of moisture during heartwood formation and thereby resulting in wetwood. Bacteria usually found in wetwood and responsible for many of the symptoms associated with wetwood are a result of the high moisture content which favors bacterial growth in wood. Presumably, the two primary sources of loss in kiln drying of western hemlock, shake and wetwood, are often intimately associated.
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    Wood science and technology 6 (1972), S. 121-127 
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    Notes: Summary Since the discovery of tyloses in the secondary xylem of angiosperms, their occurence has been noted only for vessels, although parenchyma cells necessary for their formation are also associated with fibriform elements. Sporadic remarks about tyloses in tracheids related to gymnosperm species, and the only observation on tyloses in angiosperm tracheids has been identified as an error. An anatomical investigation of various magnoliaceous timbers has now demonstrated that a development of tyloses in fibre-tracheids can also be regarded as a part of the normal transition from sapwood to heartwood in angiosperms. More than half of the 22 species studied were characterized not only by tyloses in the vessels but also in the fibretracheids. All the main genera with the exception of Liriodendron show the development of tyloses in the two different xylem elements. Distribution, frequency, and type of tyloses in the fibretracheids are comparable with those in the vessels.—Further investigations on other species of Magnoliaceae are undertaken in order to clarify possible anatomical relations regarding the development of tyloses.
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    Zoomorphology 71 (1972), S. 160-179 
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    Notes: Abstract Ecdysis of the embryonic cuticle has been studied in detail. The initiation and mechanical processes involved in this ecdysis, and the associated differential size increases of cuticular parts have been given most attention. The roles of air swallowing and of thoracic contraction are most imoprtant for rupturing the old cuticle, while abdominal contractions assist the whole process. Some specialized cuticular structures are described.
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    Notes: Abstract The turbellarian Triloborhynchus psilastericola n.sp. (family Pterastericolidae) occurs in the starfish Psilaster andromeda. On approaching maturation it moves from the host's coelom into the glandular pockets of the pyloric caeca with simultaneous loss of almost the entire ciliation. Mature turbellarians feed on the tissue of the pyloric caeca.
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    Zoomorphology 72 (1972), S. 1-25 
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    Notes: Abstract The spinning apparatus of the “Haplogynae” was studied in cribellate and ecribellate families of this group. Profound differences were encountered between the species investigated. It is concluded that the group of the “Haplogynae” is polyphyletic and can not be maintained in a phylogenetic system of the Araneae.
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    Description / Table of Contents: Zusammenfassung 1. Holzbienen verwenden beim Nektarraub zum Durchlöchern enger Blumenkronröhren nicht die Mandibeln, sondern den vorgestreckten stärren Rüssel als dolchartiges Stechorgan. Ihr Rüssel ist vor allem durch eine stärkere Sklerotisierung, Umformung and Verfalzung der Galeae der Maxillen funktionell zu einem kräftigen Stechorgan geworden. In Übereinstimmung damit wird der Rüssel in Funktionsstellung am Kopf stabiler verankert. Sie verwenden den Rüssel in erster Linie zum Öffnen mechanisch schwer zugänglicher Nektarquellen. 2. Solche schwer zugänglichen Nektarquellen linden sich z. B. in den Blüten von Calotropis procera. Der Eingangsschlitz der Nektarbehälter ist zwar federnd, aber so fest geschlossen, daß ihn nur Holzbienen mit ihrem kräftigen und starren Russel öffnen können. In diesem Zusammenhang wird Calotropis procera erneut als X ylocopa Blume erkannt. 3. Die Holzbienen wurden vor allem wegen der dichten und kräftigen Behaarung ihrer Hinterbeine bisher zumeist als reine Beinsammler angesehen. Sie sind aber, wenn nicht vorwiegend, so doch in gleichem Maße Kropfsammler, die den vom Körperrücken abgekehrten Blütenstaub im Kropf heimtragen. Ein wahrscheinlich ursprünglich nur der Reinigung der Vorderbeine dienender Putzapparat an den Maxillen wird als ein sehr wirksamer Pollenabnehmer erkannt. Er befindet sich an den Stipites der Maxillen and dient der Übernahme des Pollens von den Vorderbeinen durch die Mundteile.
    Notes: Summary 1. Carpenter bees, if they are nectar robbing, do not use the mandibles for the perforation of a narrow flowertube, but their strong proboscis which when it is stretched out, is used as a piercing organ, like a case-knife. The galeae of the maxillae are not only heavy sclerotised, but also transformed and linked together tightly, which form the piercing organ. In the main the carpenter bees use their strong proboscis for the opening of such nectaries or nectarholders which are difficult accessible. 2. Such nectarholders we find in the blossoms of Calotropis procera. The lips of the narrow entrance to the nectar are pressed together very strongly so that it only can be opened by the hard proboscis of a carpenter bee. Calotropis procera therefore is called a Xylocopa-flower. 3. Because of the very hairy metatarsus and tibia of the hind legs, the Xylocopa bees were designed mainly as podilegide bees. But at least in the same degree they collect pollen with their fore legs and mouthparts and transport it home within their foregut. A comb on the stipes of their maxillae which probabely was used originally as a cleaning one, is now working very successfully as a pollen collector. The function of this morphological detail of the proboscis was unknown till today.
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    Notes: Abstract The spermatophores of Amblypygi and Uropygi are complicated structurs and vary in different species. In Mastigoproctus, the size and shape of the spermatophores prevent bastardation between M. giganteus and M. brasilianus. Taxonomic and phylogenetical implications are discussed.
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    Zoomorphology 71 (1972), S. 150-159 
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    Notes: Abstract The neurosecretion of the subeerebral glands (part of the so-called retrocerebral organ) in the rotifer Brachionus plicatilis is described.
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    Zoomorphology 71 (1972), S. 189-202 
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    Notes: Abstract The integument of the Kinorhynch Trachydemus giganteus was investigated by means of electron microscope. It was found that the epidermis is composed of individual cells. The cuticle and receptor cells, which in part bear an apical cilium, exhibit arthropod characteristics.
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  • 39
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    Notes: Abstract In the electric fishes Gymnarchus niloticus (Mormyriformes) and Electrophorus electricus (Gymnotoidei, Cypriniformes) the specific sensory organs have been counted on whole mounts of the skin. Their number exceeds that one which would fulfill the theoretical demands for a highly sensitive electro-receptor system.
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    Zoomorphology 72 (1972), S. 26-35 
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    Description / Table of Contents: Zusammenfassung Von Proben aus dem Ross-Meer (Antarktis) liegen vier Echiurida-Kopflappen vor, welche zwei neuen Arten angehören: 1. Der Kopflappen von Binoraphorus geminolobotus n. g. n. sp. weist eine symmetrische Verdoppelung im Organaufbau auf, — einschließlich einer paarigen äuBeren Mundöffnung; der ventromediane Längssteg und die terminale Zweilappigkeit vertiefen die Besonderheiten des Zwillings-Kopflappen. 2. Die drei Kopflappen von Echiurus torulobotus n.sp. zeigen gleich jenen des arktisch-borealen E. echiurus einen proximalen medioventralen Wulst; die neue Art erweist sich jedoch im geographischen Vorkommen eindeutig abgegrenzt.
    Notes: Summary Samples from the Ross Sea (Antarctic) contained four prostomia (“probosces”) of Echiurida which belong to two new species: 1. The prostomium of Binoraphorus geminolobotus n. g. n. sp. shows a symmetrical arrangement of double organs. This unique dual prostomium is externally marked by two mouth openings, by a ventromedian ridge and by a bilobed distal end. 2. The typical echiurid prostomium of Echiurus torulobotus n. sp. possesses a proximal swelling similar to that of Echiurus echiurus. It must be stated, however, that the latter is without exception a boreal-arctic form, and the present prostomia belong therefore to a geographically separated species.
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    Zoomorphology 73 (1972), S. 315-324 
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    Description / Table of Contents: Zusammenfassung Elektronenmikroskopische Untersuchungen am Auge von Ceratophyllus zeigen, daß es keinem der bislang beschriebenen Ommatiden-Bautypen bei Insekten zuzuordnen ist. Der Rezeptorteil des Auges besteht aus über 100 Retinulazellen. (Beim Igelfloh Archaeopsylla sind es sogar über 300.) Diese bilden im Zentrum ein sehr voluminöses Rhabdom. Auf Querschnitten ist dieses aus Bändern geformt, die unregelmäßige Muster bilden. Außerdem liegen um dieses zentrale Rhabdom herum noch zahlreiche kleinere Rhabdomere bzw. Rhabdome. In ihrer Gesamtheit sollen sic als laterales Rhabdom bezeichnet werden. Distal ist es mit dem zentralen verbunden, basalwärts trennt es sich von diesem, um dann noch weiter proximal dessen zentrale Position einzunchmen. Beim Igelfloh dagegen ist nur ein Zentralrhabdom ausgebildet. Die von einer Neurallamelle umgebenen Axone sind von unterschiedlicher Dicke. Sic verlassen den Bereich der Sehzellen in kleineren oder größeren Gruppen, treten jedoch schon nach einer kurzen Strecke zu einem einheitlichen Nerven zusammen. Der cuticulare Teil des Auges besteht aus einer dicken, bikonvexen, außen völlig glatten Cornealinse und einem tief in das Innere des Kopfes hineinragenden Becher. Dieser besitzt proximal eine exzentrisch liegende Öffnung für die Axone, Tracheolen und die Lymphe. Becher und Linse werden von schmalen Epithelzellen ausgekleidet. Ein Kristallkegel ist nicht vorhanden. Schirmpigmenthaltige Zellen fehlen eben-falls.
    Notes: Summary Electron microscopic investigations on the eye of Ceratophyllus prove that its construction does not match any type of ommatidia as yet described in insects. The perceiving part of the eye consists of more than I00 retinula cells (in the hedgehog flea more than 300). They form a bulky central rhabdom. Cross-sections of the rhabdom reveal ligaments forming irregular patterns. The central rhabdom is surrounded by numerous smaller rhabdoms (or rhabdomeres), collectively described as a lateral rhabdom. At the distal end the lateral and central rhabdoms are connected; towards the basis they part, and further proximally, the lateral rhabdom assumes the position of the central rhabdom. However, in Archaeopsylla only a central rhabdom occurs. The axons are surrounded by a neural lamina, and vary in diameter. They leave the retinular area in smaller or larger groups, but soon merge to form a homogeneous nerve. The cuticula part of the eye consists of a thick biconvex corneal lens completely smooth on its surface and of a cup projecting deeply into the head. Proximally, the cup has a eccentric opening through which pass axons, trachooles and hemolymph. Cup and lens are lined with small epithelial cells. Neither cristal cone nor as pigment cells are present.
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    Wood science and technology 6 (1972), S. 81-84 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary In both Douglas-fir and aspen wood, the fiber saturation point of early wood is greater than that of late wood, solvent extraction lowers the fiber saturation point, and the fiber saturation point for reaction wood is less than that for whole wood.
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    Wood science and technology 6 (1972), S. 185-195 
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    Notes: Summary Fibrillar angles were determined in the secondary wall layers of three rings across the stem of a mature red pine. The Senarmont compensation method was adopted for this study since it gives results for all three wall layers. It involves the determination of birefringence in a series of sections cut at various angles to the long axis of the tracheids. Maxima and minima in the resultant plots of birefringence versus section angle correspond to fibrillar orientations. In the “early latewood” of each ring, the S2 layr was found to contain a single Z helix of small fibrillar angle and the S1 dual S and Z helices of much flatter orientation. Results for S3 were found to be so close to those for the corresponding S2 layers that there was some doubt as to their validity. In each layer a slight decrease in fibrillar angle was observed between rings 4 (juvenile wood) and 12 (transition zone); a sharper decrease was seen between ring 12 and the mature ring 20. This trend corresponds inversely to tracheid length differences for the three rings. Correlations of tracheid wall thickness and overall cross-sectional dimensions with the fibrillar angle variations were less readily apparent.
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    Wood science and technology 6 (1972), S. 249-250 
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 45
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The incidence of non-linearity with stress in the rheological behaviour of wood in bending was shown earlier to occur at an unexpectedly low stress. This has been further confirmed by the study of an additional species, alpine ash. Tests on hoop pine, one of the species previously studied in bending, have shown that in compression, non-linearity first occurs at stresses which are a much higher fraction of the ultimate stress than in bending, but in approximately the same range of actual stress. This suggests that the cause of non-linearity at such a low stress in bending lies in the fact that the compressive strength is considerably lower than the bending strength. The stress on the compression face of a beam reaches a high percentage of the ultimate compressive strength by the time the bending stress reaches the limit of proportionality in bending and the nonlinear effects in a beam are attributable mainly to stresses near the compression face. A marked effect of temperature on fractional total creep for hoop pine in compression was found even within the range 20 to 50° C, the creep increasing by a factor of about 2.5 in this range.
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    Wood science and technology 6 (1972), S. 272-283 
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    Notes: Summary Plastic stress arising in wood during drying is calculated according to the theoretical model developed earlier. The mechanism of stress reversal and the type of resudual stress corresponding to different values of material constants are shown. The results are in qualitative agreement with experimental evidence.
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    Wood science and technology 6 (1972), S. 284-292 
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    Notes: Summary A relation describing the shrinkage properties of a fibre-composite is applied to a multilayered thin-walled model of wood. With the theory developed it is possible to specify shrinkage with respect to moisture content, as well as with factors involved in cell-wall geometry and composition. However, until more is known of the properties of the water-reactive matrix component of the composite it is only practicable to describe shrinkage with respect to the geometrical and compositional factors at the moisture-content of the stress free state.
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    Notes: Summary The muscles moving, directly or indirectly, the anterior extremity, the action of the muscles, and the skeletal elements on which these muscles attach are described in Rousettus aegyptiacus (É. Geoffrey) (Pteropodidae). On the whole the morphological pattern and action of the muscles are the same as in microchiropteran bats, though there are some differences. The description, high-speed films, and flash photographs are made the basis of functional aspects. 1. Rousettus aegyptiacus has a very low midventral sternal ridge. The sternum also has three keels, on which a median ligamentous sheet attaches. This ligament and the keels form an enlarged area of attachment for the pectoralis muscle without any appreciable increase in weight. 2. The cross sections of the digits are described. The digits are shaped in such a way as to have their largest diameters in those planes where the bending forces are largest, thereby keeping low the weight while still possessing rigidity in the important directions. However, this flattening of the digits in certain planes is less pronounced in Rousettus aegyptiacus than in many micro chiropteran species. 3. The metacarpals are short in relation to the entire digits, as compared with many microchiropteran species. This permits the bat to get a potentially high camber of the wing during the downstroke. During the later part of the upstroke the digits are highly flexed, folding the hand wing, to reduce the drag. A relatively short metacarpal contributes to giving a small area of the hand wing meeting the airstream during the upstroke. 4. The rigid unit formed by the second and third digits is very broad in megachiropteran bats. Musculus palmaris longus is very powerful in Rousettus aegyptiacus in comparison with most microchiropteran bats so far investigated. These features contribute to giving high camber of the wing. 5. Rousettus aegyptiacus has a powerful flexor muscle of the radius, Musculus brachio-radialis, which is unusual in microchiropteran bats. 6. Megachiropteran bats, so far investigated, possess more powerful membrane muscles than do the small microchiropteran bats. Flight characteristics: The wing loading for females is ca. 21 NM−2, for males ca. 30 Nm−2, the aspect ratio ca. 5.8, and the stroke frequency ca. 8 per sec in slow level flight, ca. 3.3 m per sec.
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    Zoomorphology 73 (1972), S. 145-162 
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    Notes: Summary A muscle receptor organ is present in the mandible of macruran decapods. The mandibular muscle receptor organ (Mand. MRO) of Homarus gammarus (L.) consists of a ribbon of muscle innervated at its ventral insertion by 10–20 multiterminal sensory neurones. The sensory cells have a small number of dendritic processes. The receptor muscle exhibits some structural properties of both fast and slow muscle. The mean sarcomere length is similar to that of the slow abdominal MRO but the receptor muscle in cross section has a punctate distribution of myofibril bundles more typical of fast muscle.
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    Zoomorphology 73 (1972), S. 163-194 
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    Notes: Summary Both Belostoma and Ranatra possess I–II, subepimeral, thoracic subalar, and abdominal subalar air stores. In Belostoma, unlike Ranatra, the subepimeral air store is greatly enlarged, the abdominal subalar store is partially exposed to the water, and a fully exposed ventral abdominal air store is also present. All the air stores of Ranatra are normally concealed. The mesothoracic and metathoracic spiracles, which open onto the I–II and subepimeral air stores respectively, are of limited permeability. They appear to have less respiratory importance than the large and highly permeable first abdominal spiracles, which lie in the subalar air space and can probably exhale and inhale large amounts of air. The large eighth abdominal spiracles, which lie at the base of the siphon or retractile organ, can also inhale or exhale much air in Ranatra but appear to be mainly exhalant in Belostoma. The smaller second through seventh abdominal spiracles structurally resemble the eighth ones in Belostoma and open onto the ventral abdominal air store. In Ranatra they appear to have no significant respiratory function. Both genera obtain atmospheric air and give off exhaled air by means of the posterior retractile organ or siphon. The two types of air appear to follow different pathways in the two genera. In Ranatra atmospheric air appears to enter the tracheal system mainly or entirely through the eighth abdominal spiracles and then passes through the first abdominal spiracles into the subalar space. Exhaled air follows the reverse pathway. In Belostoma, however, atmospheric air probably enters the tracheae mainly through the first abdominal spiracles; it is conveyed to these spiracles from the retractile organ through the subalar space or, more indirectly, through the ventral abdominal air store. Air exhaled through the first abdominal spiracles follows the reverse route; the eighth abdominal spiracles can also exhale directly into the base of the retractile organ. During underwater respiration the abdominal portion of the subalar air store appears to be the main reservoir for oxygen. The subalar oxygen is initially atmospheric, and is supplemented, during submersion, by other sources of oxygen. Belostoma may use its exposed ventral abdominal air store, and its partially exposed abdominal subalar one, as “physical gills”; both these stores communicate with the inhalant first abdominal spiracles. Ranatra, none of whose air stores are normally exposed, appears, to be less capable of utilizing dissolved oxygen, but the considerable amount of atmospheric oxygen in the elongated siphon may be inhaled, during submersion, through the eighth abdominal spiracles. In both genera the thoracic air stores appear to be of less respiratory importance than the abdominal ones. They do not appear capable of obtaining large amounts of oxygen, and the thoracic spiracles are relatively impermeable. All the air stores, however, serve to protect the spiracles against the entry of water, and also contribute to the body's hydrostatic balance. It is also possible that some of the air stores play a role in pressure reception. The literature indicates much intergeneric variation in the respiration of Belostomatidae and Nepidae. In the Belostomatidae there is considerable variation in the extent of the ventral abdominal air store and in the roles of the subalar air store and the spiracles. The Nepidae show differences in their ability to utilize dissolved oxygen and in the extent of the subepimeral air store.
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    Description / Table of Contents: Zusammenfassung Das männliche Genitalsystem von Tarantula besteht aus paarigen Hoden, Lateraldrüsen, Ventraldrüsen und dem Genitalatrium mit dem Genitalanhang. Die Spermatozoen entwickeln sich in Spermatocysten. Sie sind zunachst langgestreckt und korkenzieherförmig. Später rollen sie sich ein and encystieren sich. In diesem Zustand werden sie in paarigen Vesicula seminalis gespeichert. Die Ventraldriisen produzieren durch holokrine Sekretion ein granuläres Sekret. Das Produkt der Lateraldrüsen ist homogen und hyalin. Beide Sekrete mischen sich nicht; sie werden in großen Sekretreservoiren gespeichert. Die Genitalanhang entsteht aus paarigen Gonopoden, die sich zunächst teilen und darn zusammenlegen und so ein hohles, kompliziertes Organ bilden. Die Spermatophore ist nicht vorgebildet, wenn das Männchen sich anschickt, sie abzusetzen. Die beiden Sekrete laufen zunächst entlang zweitr Ventralrinnen zu zwei ventralen Öffnungen. Dort werden sie am Untergrund befestigt und dann durch Anheben des Körpers zum Stiel ausgezogen. Danach werden die Ventralrinnen geschlossen, und das Sekret fließt in den zentralen Hauptraum des Genitalanhangs, der als Negativ-Form für den oberen Teil der Spermatophore dient. Dieser wird anschließend durch eine dorsale Öffnung herausgezogen. Die weiblichen Organe bestehen aus paarigen Ovarien, Ovidukten und Oviduktanhängen, einem unpaaren Uterus und dem. Genitalatrium mit den Gonopoden. Die Oocyten treten fresh aus dem Ovar aus, mit dem sic durch einen Funiculus verbunden bleiben. In der Leibeshöhle vollzieht sich der Dottereinbau in zwei Phasen; die zweite beginnt normalerweise nach der Paarung. Doch bleiben immer einige ruhende Oocyten, die nicht die zweite Vitellogenese-Phase beginnen. Kurz vor der Eiablage dehnen sich die Funiculi stark und lassen die Eier wahrscheinlich zurück ins Ovar schlüpfen. Nach der Paarung werden außerdem die Ovarien, Ovidukte und Oviduktanhänge sekretorisch tätig. Sie liefern ein aus fädigen Elementen bestehendes Sekret, in das viele Hämocyten einwandern. Vor der Eiablage tritt dieses Material aus der Geschlechtsöffnung und bildet den Brutsack. Das weibliche Genitalatrium ist ein weiter Baum. Die Gonopoden sind Schwellkörper, die dem Genitaloperculum innen aufsitzen. Bei Tarantula tragen sie je ein klauenartiges Sklerit, mit dem die Samenpakete aus den Spermatophoren gerissen werden. Das Sperma wird in zwei Receptacula seminis gespeichert, deren Öffnungen direkt unter den Basen der Sklerite liegen. Charinus brasilianus besitzt keine solchen Sklerite und keine Receptacula; die Spermien werden in einer hinteren Ausbuchtung des Genitalatriums gespeichert. Bei jeder Eiablage werden alle Spermien aufgebraucht. Bei Häutungen bleibt das Sperma in der Exuvie und geht verloren. Die Weibchen miissen sich darum vor jeder Fortpflanzungsperiode erneut paaren.
    Notes: Summary The male genital system of Tarantula consists of paired testes, ventral glands, lateral glands, and the genital chamber with the cone like spermatophore organ. Spermatogenesis occurs in spermatocysts. Mature spermatozoa first are corkscrew like in shape but later become rolled up and encysted. They are stored in a pair of vesicula seminalis. In the ventral glands, secretion is holocrinous and a granular substance is formed. The lateral glands produce a transparent, homogenous material. Both substances do not mix; they are stored in large reservoirs. The cone like spermatophore organ is a complex structure formed by a pair of gonopods which first splits into two paires and later unites to form a hollow organ with a complicated system of cavities. No precursor of a spermatophore exists when a male starts depositing the spermatophore. The secreted material first runs along latero-ventral tubes to two ventral openings. There, it is fixed to the substrate and formed to the spermatophore stalk by the male's rising its body. Thereafter, the central cavity of the spermatophore organ is filled with secreted material and acts as a matrix which presses the upper parts of the spermatophore. This is finally pulled out through a mid-dorsal opening. The female organs consist of paired ovaries and oviducts, an unpaired uterus, and the genital chamber with the gonopods. The oocytes develop outside the ovary but remain fixed to it by a solid funiculus. There are two phases of vitellogenesis, the second one is started after mating. But there are allways a number of resting oocytes which do not enter the second phase of vitellogenesis. Since whip spiders may live for many years and may lay egss one to three times a year these are stored for later breeding periods. Before oviposition, the egg stalks widen, and the eggs finally pass through the funiculi into the ovary. Mating not only induces the second phase of vitellogenesis but also causes the ovary and oviducts to secret a filamentous material which is invaded by many haemocytes. Immediately before oviposition, this material is extruded. It surrounds the eggs and later hardens and forms the egg sac. The female genital atrium is a broad and wide cavity. The gonopods are two protrudible organs which, like the male organs, originate from the inner wall of the genital operculum. In Tarantula, each gonopod bears a claw like sclerite pointed backwards and inwards. By means of these sclerites the sperm packages are pulled out of the spermatophore. Simultaneously, the sperm is pressed out of the sperm packages, which may remain underneath the sclerites for many days, and sucked into two seminal receptacles laying just beneath the bases of the claw like sclerites. In Charinus brasilianus, the gonopods are cone like and lack sclerites and seminal receptacles. The sperm, in this species, is stored within a posterior pocket of the genital atrium. At oviposition, all stored sperm is used up, and at each molt all sperm is lost. Females therefore have to be reinseminated after breeding and molting.
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    Zoomorphology 71 (1972), S. 52-104 
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    Notes: Abstract The differentiation of the endocrine glands in the embryo of Oncopeltus fasciatus is described. The function of these glands can be correlated with the embryonic moults. The nuclei of some tissues already become polyploid in the embryo. It is discussed whether the endomitotic growth is dependent upon the function of the endocrine glands.
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    Zoomorphology 71 (1972), S. 128-149 
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    Notes: Abstract The morphological arrangement of the antennal joints and their significance for the complex antennal movements are investigated. Particular value is attached to the mechanoreceptors of the 2. segment because of their importance for the function of the antennae as air current sense organs.
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    Wood science and technology 6 (1972), S. 43-57 
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    Notes: Summary Measurements were made of the principal components of the creep compliance tensor in the radial-longitudinal and the tangential-longitudinal planes of Douglas-fir at 10 percent moisture content. Extensional creep compliance measurements at angles to the grain were also made. The results show that creep parallel to grain occurs at an increase in volume, and that creep at angles to the grain can be predicted from standard transformation equations. It is concluded that wood can be regarded as a linear orthotropic viscoelastic material.
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    Wood science and technology 6 (1972), S. 78-80 
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    Wood science and technology 6 (1972), S. 1-42 
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    Notes: Abstract The study of adhesion in wood and wood-based products becomes increasingly important as work continues toward greater utilization of our total forest resources. The present quality of adhesively bonded wood products will be improved in order to achieve bond quality that harnesses the full strength of wood and, more importantly, leads to greatly enhanced bond durability. These goals will primarily be reached through developing a chemically-anchored bond interface and resin systems that are more flexible and compatible in the cured state. This paper presents a selected review of current findings and thought in the general field of surface and interfacial adhesion, and attempts to give a detailed look at efforts in wood science to understand basic phenomena of adhesion in wood and apply them in achieving a strong and durable bonded state. A brief introductory discussion on the nature of the basic forces involved in all interactions between materials at the atomic and molecular level is included. The general field of interfacial adhesion is reviewed in order to find important factors basic to the adhesion phenomena that have survived long, intensive research efforts in this field. Finally, an in-depth look is taken at interfacial adhesion in wood science.
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    Wood science and technology 6 (1972), S. 58-58 
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    Wood science and technology 6 (1972), S. 251-262 
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    Notes: Summary An important relationship has been shown between measurements of expansion of the radial dimension of cells during the lignification phase of differentiation, widely reported swelling of the thickness of cell walls during lignification, the fundamental mechanics of strain interactions in the three cardinal directions in materials generally, and a theory linking anisotropic behaviour of wood to its microfibril arrangement and the effect of encrusting substances in the cell wall. As a consequence, it has been deduced that tangential, longitudinal and radial stresses of substantial magnitude are generated in wood tissues as a result of lignification. In comparisons with measured growth stresses, it has been concluded that they are probably identical with the stresses that would develop as a result of lignification of the cell walls.
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    Wood science and technology 6 (1972), S. 263-271 
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    Notes: Summary Measurements of the gas pressure required to displace water and allow gas bubbles to start continuously passing through the void structure of hardwood cross sections varying in thickness from 0.1 ... 10.0 cm have been used to calculate the maximum effective opening diameters. These diameters decrease with an increase in the thickness of the cross sections, as is the case for softwoods. Extrapolation of diameter—thickness plots to zero thickness gives the maximum vessel diameters, which agree well with microscopically determined values. The relatively small decrease in the maximum effective opening diameters with increasing thickness of the cross sections for most of the sapwood samples tested is due to irregularities in the vessel diameters and presence of perforation plates at the ends of the vessel segments. The decrease in the maximum effective opening diameter with an increase in the thickness of the cross sections is greater for the heartwood than for the sapwood. The ratio of the sapwood to the heartwood values tends to become constant between cross section thicknesses of 2.5 and 5.0 cm. This ratio was small for tyloses free northern red oak but appreciable for the hardwoods containing tyloses in the heartwood. Air drying followed by oven drying and resaturating of the specimens with water caused only small variable changes in the maximum effective opening diameters that were within the range of experimental accuracy of the measurements (approximately 5%).
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    Wood science and technology 6 (1972), S. 302-313 
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    Notes: Summary New displacement equations for the static bending of six common types of simple, finite anisotropic or orthotropic beams are presented. The effect of shear and Poisson's ratios in the determination of Young's modulus by static bending is discussed.
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    Wood science and technology 6 (1972), S. 314-316 
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    Wood science and technology 6 (1972), S. 128-137 
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    Notes: Summary The effects of creep at constant conditions of moisture content and the effects of deformations occurring during cycling of moisture content have been studied in loaded beams of particleboard and hardboard. The variations in stiffness in loaded and unloaded beams of particleboard during moisture cycling were also determined. Contrary to the findings of some workers but in agreement with the findings of another, the increases in the deflections of loaded beams of particleboard during cycling of moisture content were due mainly to desorption of moisture. Qualitatively similar behaviour was found for particleboard, hardboard and wood but quantitatively the effects were greatest in particleboard and hardboard. It appears that the basic mechanism of the transient effects in bending, arising with the simultaneous action of load and change in moisture content, may be similar in wood, particleboard and hardboard.
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    Wood science and technology 6 (1972), S. 138-156 
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    Notes: Abstract Wood tracheids are essentially tubular structures but wood cross sections are characterized by large numbers of triple points or junctures of wall segments from three adjacent cells. A symmetric triple point is taken as an approximation to the basic unit of wood structure. This element is analysed as a linearly elastic, isotropic body. It is shown that bending effects enhance the deformations arising from simple strains so that the overall response of the element is anisotropic. The resulting stiffnesses are ordered $$E_L \user2{ 〉 }E_R \user2{ 〉 }G_{LR} \sim G_{LT} \user2{ 〉 }E_T \user2{ 〉 }G_{RT} $$ for what are considered to be fairly typical element geometries. It is shown that for all geometries the longitudinal Youngs modulus is proportional to the volume fraction of cell wall material.
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    Wood science and technology 6 (1972), S. 157-161 
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    Notes: Summary The swelling behaviour of an elastic fibre reinforced composite consisting of an inert fibrous phase embedded in a water reactive matrix is described. It is supposed that the addition of water causes the matrix to swell and become more compliant while the fibres passively resist the swelling stresses exerted by the matrix. A concise relation for the shrinkage or swelling strain is derived in terms of moisture content, the volume proportions of the phases, the overall elastic constants of the composite, the elastic constants of the matrix, and the moisture content at which the reinforcing elements are stress free.
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    Wood science and technology 6 (1972), S. 204-214 
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    Notes: Summary The analogy between thermal stress and swelling (drying) stress in wood makes it possible to give mathematical formulae for calculating the drying and swelling stresses in many situations. The models allow for viscoelastic and plastic phenomena.
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    Wood science and technology 6 (1972), S. 293-301 
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    Notes: Summary Incremental longitudinal shrinkage has been measured on 44 samples of Pinus radiata at each 5% increment of moisture content from 0 to 25%. The samples range in mean microfibril angle from 10° to 40°. The data is presented in the form of a family of curves, of incremental shrinkage against microfibril angle, for each moisture content. This family of curves compares very closely with those derived theoretically by Barber [1968] and Cave [1972] based on considering the cell wall as a fibre composite of cellulose microfibrils embedded in a matrix which swells on wetting and whose shear modulus is a function of moisture content.
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    Wood science and technology 6 (1972), S. 317-318 
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    ISSN: 1432-2099
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    Topics: Biology , Physics
    Description / Table of Contents: Zusammenfassung In der Arbeit wird eine Variation der indirekten Meßmethode der elektrischen Leitfähigkeit des Zytoplasma dargestellt, welche ausschließlich die Zweipunktmessung der Leitfähigkeit der Zellsuspension bei niedriger und hoher Frequenz umfaßt. Es wurde die empirische Abhängigkeit angegeben, die die Grundlage der Methode bildet. Diese Abhängigkeit wurde für die Erythrozytensuspension in 0,9% wäßriger NaCl-Lösung und für das menschliche Blut geprüft. Für diese Art der Suspension wurden die Meß-frequenzen, die Niederfrequenz und die Hochfrequenz, bestimmt. Es wurde eine gute Übereinstimmung der spezifischen Leitfähigkeit des aus den Erythrozyten isolierten Zytoplasmas (ϰ1=5,36mS/cm) mit den mit Hilfe der vorgeschlagenen Methode erhaltenen Angaben erzielt.
    Notes: Summary A variety of the indirect method of measuring the electric conductivity of the cytoplasm is described which is reduced to the double point measurement of the cell suspension conductivity at high and low frequency. An empirical dependence is shown on which this method has been based. This dependence has been verified for the suspension of erythrocytes in 0.9% aqueous solution of NaCl as well as for human blood. The measuring frequencies Fn and Fw for this type of suspension were defined. The agreement of the specific conductivity of cytoplasm isolated from erythrocytes (χ1=5.36ms/cm) with the data achieved by the described method is good.
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    Radiation and environmental biophysics 8 (1972), S. 316-325 
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    Topics: Biology , Physics
    Description / Table of Contents: Zusammenfassung Im zweiten Teil dieser Veröffentlichung werden kalorimetrische Untersuchungen zum Wachstum von Mikroorganismen auf festen Nährmedien beschrieben und mit den Ergebnissen des Teils I verglichen. Durch die hohe Diffusionsgeschwindigkeit der Glucose im Agar (D=0,55 cm2/d) kann die gesamte Energiequelle des Mediums beim Stoffwechsel ausgenutzt werden. Die pro Gramm vergorener Glucose abgegebene Wärme liegt etwas niedriger als die vergleichbaren Werte in flüssigen Kulturen.
    Notes: Summary In the second part of this paper growth of the yeastSaccharomyces on nutrient agar is followed by a Microcalorimeter E. Calvet. The shape of the thermograms is similar to that of liquid cultures except of a small peak at the beginning of the growth. Although the cells are growing on the surface of the nutrient agar the whole source of energy is used during the metabolism. The change of enthalpy during fermentation is 82 cal/g glucose on a complex medium and 74 cal/g on a synthetic one. The small peak and oscillations at the end of the respiration phase may be due to diffusion processes in the agar. For the constant of diffusion of glucose in agar we findD=0,55 cm2/d which corresponds to figures in the literature.
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    Mathematische Zeitschrift 124 (1972), S. 1-8 
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    Mathematische Zeitschrift 124 (1972), S. 20-22 
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    Mathematische Zeitschrift 124 (1972), S. 9-19 
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    Mathematische Zeitschrift 124 (1972), S. 23-36 
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    Mathematische Zeitschrift 124 (1972), S. 37-46 
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    Mathematische Zeitschrift 124 (1972), S. 51-63 
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    Mathematische Zeitschrift 124 (1972), S. 47-50 
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    Mathematische Zeitschrift 124 (1972), S. 64-66 
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    Mathematische Zeitschrift 124 (1972), S. 67-72 
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    Mathematische Zeitschrift 124 (1972), S. 73-78 
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    Mathematische Zeitschrift 124 (1972), S. 79-82 
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    Mathematische Zeitschrift 124 (1972), S. 83-88 
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    Mathematische Zeitschrift 124 (1972), S. 89-99 
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    Mathematische Zeitschrift 124 (1972), S. 119-132 
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    Mathematische Zeitschrift 124 (1972), S. 100-118 
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    Mathematische Zeitschrift 124 (1972), S. 133-140 
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    Mathematische Zeitschrift 124 (1972), S. 141-168 
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    Mathematische Zeitschrift 124 (1972), S. 191-198 
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    Mathematische Zeitschrift 124 (1972), S. 169-185 
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    Mathematische Zeitschrift 124 (1972), S. 186-190 
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    Mathematische Zeitschrift 124 (1972), S. 199-202 
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    Mathematische Zeitschrift 124 (1972), S. 203-207 
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    Mathematische Zeitschrift 124 (1972), S. 208-212 
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    Mathematische Zeitschrift 124 (1972), S. 213-214 
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    Mathematische Zeitschrift 124 (1972), S. 215-236 
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    Mathematische Zeitschrift 124 (1972), S. 237-249 
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    Mathematische Zeitschrift 124 (1972), S. 250-254 
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    Mathematische Zeitschrift 124 (1972), S. 255-258 
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    Mathematische Zeitschrift 124 (1972), S. 259-260 
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    Mathematische Zeitschrift 124 (1972), S. 261-265 
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    Mathematische Zeitschrift 124 (1972), S. 266-272 
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