This study is the first attempt to describe the ultrastructure and functional morphology of the dermal glands in Limnochares aquatica (L., 1758). The dermal glands were studied using light-optical, SEM and TEM microscopy methods during different stages of their activity. In contrast to the vast majority of other fresh water mites, dermal glands of the studied species are originally multiplied and scattered freely over the mite body surface. The opening of the glands is saddle-like, formed of several tight cuticular folds and oriented freely to the long axis of the mite body. Either a small cuticular spine or, rarely, a slim sensitive seta is placed on one pole of the opening. On the inside, the central gland portion is provided with a complex cuticular helicoid armature. The glands are composed of prismatic cells situated around the intra-alveolar lumen, variously present, and look like a fig-fruit with the basal surface facing the body cavity. The glands are provided with extremely numerous microtubules, frequently arranged in bundles, and totally devoid of synthetic apparatus such as RER cisterns and Golgi bodies. Three states of the gland morphology depending on their functional activity may be recognized: (i) glands without secretion with highly folded cell walls and numerous microtubules within the cytoplasm, (ii) glands with an electron-dense granular secretion in the expanded vacuoles and (iii) glands with the secretion totally extruded presenting giant empty vacuoles bordered with slim cytoplasmic strips on the periphery. Summer specimens usually show the first gland state, whereas winter specimens, conversely, more often demonstrate the second and the third states. This situation may depend on some factors like changes of the seasonal temperature, pH, or oxygenation of the ambient water. On the assumption of the morphological characters, dermal glands may be classified not as secretory but as a special additional excretory organ system of the body cavity. Despite the glands lack cambial cells, restoration of functions after releasing of 'secretion' looks possible. Organization of dermal glands is discussed in comparison to other water mites studied.

中文翻译：

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淡水螨Limnochares aquatica（L.，1758）（Acariformes，Limnocharidae）中真皮腺的超微结构和功能形态。

这项研究是描述水生Limnochares aquatica（L.，1758）的真皮腺的超微结构和功能形态的首次尝试。使用光学，SEM和TEM显微镜方法在不同的活动阶段研究真皮腺。与绝大多数其他淡水螨相反，所研究物种的真皮腺最初在螨体表面自由繁殖并散布。腺体的开口呈马鞍状，由数个紧密的表皮褶皱形成，并自由定向于螨体的长轴。在开口的一根杆子上放一个小的表皮脊柱，或者很少有一个稀薄的敏感刚毛。在内部，中央腺体部分具有复杂的表皮螺旋电枢。腺体由位于肺泡内腔周围的棱柱形细胞组成，形态各异，看起来像无花果，其基表面面向体腔。腺体有许多微管，通常成束排列，并且完全没有诸如RER水箱和高尔基体的合成装置。可以识别出取决于其功能活性的腺体形态的三种状态：（i）腺体无分泌物，细胞壁高度折叠且胞质内有许多微管;（ii）腺体在膨胀的液泡中具有电子致密颗粒分泌物，和（ iii）分泌物完全被挤出的腺体，在周围出现细长的细胞质带，形成巨大的空泡。夏季标本通常显示第一腺体状态，而冬季标本 相反，更多地展示第二和第三状态。这种情况可能取决于某些因素，例如季节性温度，pH值的变化或环境水的氧化。根据形态特征的假设，真皮腺可不被分类为分泌物，而被分类为体腔的特殊附加排泄器官系统。尽管腺体缺少冈比亚细胞，释放“分泌物”后恢复功能仍是可能的。与研究的其他螨相比，讨论了真皮腺的组织。真皮腺可不被分类为分泌物，而可被分类为体腔的特殊附加排泄器官系统。尽管腺体缺少冈比亚细胞，释放“分泌物”后恢复功能仍是可能的。与研究的其他螨相比，讨论了真皮腺的组织。真皮腺可不被分类为分泌物，而可被分类为体腔的特殊附加排泄器官系统。尽管腺体缺少冈比亚细胞，释放“分泌物”后恢复功能仍是可能的。与研究的其他螨相比，讨论了真皮腺的组织。