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EN
Ulva flexuosa subsp. pilifera previously known from northern Poland, from the channel near Szczecin and ponds near Łódź, has recently been found in the Malta Reservoir in the Wielkopolska (West Poland) region. Specimens collected in the Wielkopolska region were examined in detail, also under a transmission electron microscope (TEM). The morphometric analysis of Ulva thalli (both young and mature specimens) was performed in order to study the differences in the ultrastructure of vegetative cells. Rectangular cells in young thalli measured from 32.21 - 55.81 μm to 20.24 – 35.12 μm, and they formed clear longitudinal rows, while cells in the mature specimens ranged from 25.09 – 47.66 μm to 18.90 – 31.56 μm. This study indicates that vegetative cells of the mature thalli show tendency towards distortions of both the longitudinal and transverse cells arrangement. This distortion is determined by the development of possible carbonate calcium crystals on the thalli surface. The ultrastructural analysis (TEM) confirmed that the structure and placement of thylakoids is genus/species specific.
EN
The morphology of Cercaria globocaudata U. Szidat, 1940, was reexamined using light and scanning electron microscopy. The armature, chaetotaxy and surface ultrastructure were investigated for the first time since the description of the cercaria in 1940. The results complete the primary description. The systematic position of this morphologically specialized furcocercaria showing mimicry to planktonic organisms is also discussed.
Folia Morphologica
|
2003
|
tom 62
|
nr 3
231-233
EN
An ultrastructural study was performed on trigeminal ganglia removed from foetuses aged 10 to 23 weeks. The first turns of lemmocyte processes around the axons were observed in the trigeminal ganglion in the 12th week of development. During the period between the 15th and the 18th weeks the myelin sheath increases in thickness and becomes a compact, laminated structure. In foetuses of 23 weeks the compact myelin sheath has up to 24 myelin lamellae.
EN
Cocconeis subantarctica sp. nov., a small monoraphid marine diatom, previously described as C. scutellum cf. var. parva Grunow, is reported from the Kerguelen Archipelago. Based on the careful re-examination of the material using SEM (scanning electron microscopy), both valves and the cingulum were described, which enabled a better classification of this small Subantarctic taxon. The shape of the frustule is widely rounded to subdiscoid, with uniseriate and radiate striae on both valves. The SV (sternum valve) areolae have rota-like hymenate pore occlusions, with larger marginal areolae separated by a hyaline rim. The RV (raphe valve) areolae are more complex than those of the SV, with several reniform concentric hymenate occlusions. This taxon has no real stauros, only one virga, which is larger on one side of each valve. The species is not a member of the Cocconeis scutellum ‘complex’, but is closely related to C. stauroneiformis despite several morphological differences.
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