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  • 1
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Zwei links und rechts im Vorderkörper von Cirrifera aculeata (Ax, 1951) (Proseriata) gelegene Zellen werden als mögliche Photoreceptoren angesprochen. In ein großes intracelluläres Lumen der linken Zelle ragen über 70 nur leicht modifizierte Cilien, daneben treten Mikrovilli und elektronendichte Granula auf. Die vermutlich lichtsensitiven Strukturen der rechten Zelle bilden dicht nebeneinander liegende röhrenartige Vakuolen, vergleichbar den Mikrovilli eines Rhabdoms. Die funktionellen und evolutiven Aspekte dieser beiden bisher unbekannten Zelltypen werden diskutiert.
    Notes: Summary Two cells which lie at the left and at the right near the anterior end of Cirrifera aculeata (Ax, 1951) (Proseriata) are interpreted as presumed photoreceptors. In the left cell up to 70 slightly modified cilia extend into a large intracellular cavity. Besides these cilia microvilli and electron-dense granules are present. The presumed light sensitive structures of the right cell are formed by tubular vacuoles which are arranged without gaps, thus comparable to the microvilli of a rhabdom. The functional and evolutionary aspects of these two cell types are discussed.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Zoomorphology 104 (1984), S. 226-230 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Für die Nematoplanidae und die Polystyliphoridae (Proseriata) wird ein besonderer Collar-Receptor-Typus beschrieben, der vom Grundmuster der entsprechenden Receptoren der übrigen Proseriata und der Rhabdocoela in zwei Punkten abweicht: (1) Die Receptoren ziehen zwischen Epidermiszellen zur Körperoberfläche. (2) Im distalen Bereich der Receptoren ist im Cytoplasma eine elektronendichte Manschette differenziert. — Zusammen mit anderen Organisationsmerkmalen wird die Manschette dieses Receptor-Typus als Synapomorphie der Nematoplanidae und Polystyliphoridae, des monophyletischen Taxon Unguiphora Sopott-Ehlers, 1984, bewertet.
    Notes: Summary In the Nematoplanidae and the Polystyliphoridae (Proseriata) a special collar receptor type is found, which differs in two points from the basic pattern of these receptors in the other Proseriata and in the Rhabdocoela: (1) The receptors run between epidermal cells to the surface. (2) In the distal region of the receptor cells an electron-dense cuff is developed. The cuff of these receptors, together with some other features of organisation, is considered to be a synapomorphy of the Nematoplanidae and the Polystyliphoridae, which together form the monophyletic taxon Unguiphora Sopott-Ehlers, 1984.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Zoomorphology 95 (1980), S. 159-167 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Stilettapparatur vonCarenscoilia bidentata Sopott besteht aus mehreren verfestigten Elementen. Diese werden in einem mehrkernigen Matrixsyncytium ausdifferenziert; während der Ontogenese entstehen zuerst periodisch quergestreifte Mikrofibrillen, an die sich elektronendichtes homogenes Material anlagert. Die Wandung der fertig ausgebildeten intracellulären Hartstrukturen besteht aus einer zentralen Lage von Mikrofibrillen, der außen elektronendichte Schichten aufliegen. Hartgebilde mit einer vergleichbaren Feinstruktur sind bisher nur von weiteren proseriaten Turbellarien, nicht jedoch von anderen Plathelminthen bekannt.
    Notes: Summary The stylet apparatus ofCarenscoilia bidentata Sopott consists of five hard elements. These are differentiated in a matrix syncytium. During the ontogeny at first microfibrils with a periodic cross-banding arise; then the microfibrils become enveloped by homogenous electron opaque materials. The wall of the developed intracellular hard elements consists of a central layer with microfibrils and outer layers of electron opaque materials. Hard differentiations with a comparable fine structure are only known from other proseriate turbellarians, but not from other platyhelminthes.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Zoomorphology 112 (1992), S. 11-15 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The photoreceptors ofPogaina suecica correspond to the type of pigment cup ocelli. Each eye consists of one cup cell and three sensory cells. The most conspicuous differentiations of these eyes are lens elements formed by giant mitochondria densely filled with homogeneous electron-dense material. From electron microscopical findings available to date it is hypothesized that mitochondrial lensing might be an autapomorphy of a taxon comprising the Provorticidae Kirgisellinae, Dalyelliidae and Graffillidae groups which are ascribed to the paraphyletic “Dalyellioida”.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Zoomorphology 86 (1977), S. 197-222 
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of monociliary receptors in 10 species of the Proseriata and Neorhabdocoela is described, with particular reference to the epidermal dendritic part. Sensory cells with a single kinocilium situated at the level of the distal epidermis membrane are considered as mechano- or chemoreceptors. There exist sensory cells with a dendrite penetrating one epidermis cell and bearing an embedded kinocilium and a collar of 8 stereocilia or ridges with a fribrillose substructure. These collared receptors probably function as mechanoreceptors. In comparison with collared sensory cells in species of other turbellarian orders, the embedded receptors in the Proseriata and Neorhabdocoela are more advanced and possess synapomorphous characteristics. With the embedded receptors a new evidence is given for the close phylogenetic relationship between the Proseriata and Neorhabdocoela. The distribution of collared cells in the animal system and their phylogenetic implication for a choanoflagellate origin of the Metazoa are briefly discussed.
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  • 6
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The intercentriolar body in the biciliary spermatids of Nematoplana coelogynoporoides and its changes during spermiogenesis are described. Different functional aspects of the body, for example its presumed role as microtubule-organising centre and its influence on cell elongation, are discussed.
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  • 7
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spermiogenesis of Invenusta aestus (Coelogynoporidae) is described based on electron microscopical observations. Special attention is paid to the intercentriolar body and the anchoring apparatus of the cilia. These organelles are differentiated at the beginning of spermatid maturation and undergo striking changes during gametogenesis. The importance of the organelles mentioned for discussion of phylogenetic relationships within the Plathelminthes is considered.
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  • 8
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The steps of spermiogenesis and the submicroscopic anatomy of male gametes in Halammovortex nigrifrons are described. During spermiogenesis the cytophore develops pseudopod-like extensions, and bung-like deposits of dark material become attached to the basal bodies of the cilia. During the phase of cell elongation, cilia stay near the edge of the cytophore. Spermatozoa bear two free cilia or flagella. The axonemata are equipped with glycogen islets appearing at regular spaces. The sperm body is characterized by dot-like dense granules linearly arranged, intense glycogen aggregations in a channel-shaped deposition and giant dense bodies. Events of spermiogenesis and the features of mature male gametes in H. nigrifrons corroborate the hypothesis of the existence of a monophylum within the Rhabdocoela encompassing several, but not all taxa of the ”Typhloplanoida” and ”Dalyellioida”. The Dalyelliidae (including the species of the Temnocephalida) belong to this monophylum.
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  • 9
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The statocyst of otoplanids is enveloped by a bipartite capsule which consists of two different extracellular matrices. This capsule encircles three different types of aciliary cells: several peripherally located flattened parietal cells, one central statolith forming cell (lithocyte) and two clusters of accessory cells. Intracapsular lumina exist which are different from extracapsular intercellular spaces. The accessory cells most probably represent those structures that are mainly involved in nervous conduction. These cells extend cytoplasmatic processes towards different peripheral regions of the statocyst where processes of outer nerve cells penetrate the capsule. The statocyst does not seem to represent a more evolved equilibrium receptor system but may function as a relatively simple aciliary sense organ suitable for positive geotactic behaviour. The otoplanid statocyst corresponds to statocysts in other lithophorous proseriates but not to statocysts in other taxa of the free-living Plathelminthes. The monophyly of a taxon Lithophora within the Proseriata is corroborated by this autapomorphic characteristic.
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  • 10
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fine-structural features of vitellaria and germaria inNematoplana coelogynoporoides are documented and compared with those of other free-living plathelminths with ectolecithal eggs. Emphasis is mainly put on the pattern of eggshell material, yolk bodies deposited in vitellocytes, and marginal granules of the female germ cells. In this species, encompassed in the taxon Proseriata Unguiphora, the eggshell granules show a meandering pattern also known from species of the taxon Proseriata Lithophora. In contrast, the yolk globules exhibit crystalline components unknown from the Lithophora. The marginal granules in the ooplasm have an extremely large diameter. They consist of a flocculent core and a crescent-shaped cortex. Marginal granules of this appearance have not been found in any other taxon of free-living Neoophora.
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