We studied the anatomy and cytology of the midgut gland (MGl) of the common spider crab Maja brachydactyla Balss, 1922 at several life stages (zoea, megalopa, first juvenile, and adult) using dissection, histology, electron microscopy, computed tomography, and micro-computed tomography (micro-CT). In newly hatched larvae, 14 blind-end tubules form the MGl. The length of the tubules increases during the larval development. In the late megalopa, the number of tubules also increases. In adults, 35,000 to 60,000 blind-ending tubules comprise the MGl. In all life stages, a square-net network of muscle fibers surround the tubules. We describe five cell types in the MGl in all larval stages, which have a similar location, histology, and ultrastructure in larvae and adults: embryonary (E-) cells, resorptive (R-) cells, fibrillar (F-) cells, blister-like (B-) cells, and midget (M-) cells. Major difference between larval and adult cells is the larger size of the adult cells. Microapocrine secretion occurs from the microvilli of the B-cells. No ultrastructural changes were observed during larval development, which suggests that the function of each cell type might be similar in all life stages. The role of each epithelial cell type in larvae and adults is discussed.

中文翻译：

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常见蜘蛛蟹Maja brachydactyla Balss，1922年（Majidae，Brachyura）的个体发育过程中中肠腺（“肝胰腺”）的形态和超微结构。

我们使用解剖，组织学，电子显微镜，计算机断层扫描和断层扫描研究了普通蜘蛛蟹Maja brachydactyla Balss（1922）在几个生命阶段（zoea，megalopa，第一个少年和成年）的中肠腺（MGl）的解剖学和细胞学。微型计算机断层扫描（micro-CT）。在新孵化的幼虫中，MG1形成了14个盲端小管。在幼体发育期间，肾小管的长度增加。在晚绝经期，肾小管的数量也增加。在成年人中，35,000至60,000个盲端小管组成了MG1。在所有生命阶段，肌肉纤维的方网网络围绕着小管。我们描述了MGl在所有幼虫阶段中的五种细胞类型，它们在幼虫和成虫中具有相似的位置，组织学和超微结构：胚胎（E-）细胞，吸收性（R-）细胞，纤维状（F-）细胞，泡状（B-）细胞和侏儒（M-）细胞。幼虫和成年细胞之间的主要区别是成年细胞的大小较大。微分泌分泌来自B细胞的微绒毛。在幼体发育过程中未观察到超微结构变化，这表明每种细胞类型的功能在所有生命阶段都可能相似。讨论了每种上皮细胞类型在幼虫和成虫中的作用。