Poprawa Izabela
Department of Animal Histology and Embryology, University of Silesia, Bankowa 9, 40-007 Katowice, Poland.
Zoolog Sci. 2011 Jan;28(1):37-40. doi: 10.2108/zsj.28.37.
The egg capsule of Isohypsibius granulifer granulifer Thulin 1928 (Eutardigrada: Hypsibiidae) is composed of two shells: the thin vitelline envelope and the multilayered chorion. The process of the formation of the egg shell begins in middle vitellogenesis. The I. g. granulifer vitelline envelope is of the primary type (secreted by the oocyte), but the chorion should be regarded as a mixed type: primary (secreted by the oocyte), and secondary (produced by the cells of gonad wall). During early choriogenesis, the parts of the chorion are produced and then connected into a permanent layer. The completely developed chorion consists of three layers: (1) the inner, medium electron dense layer; (2) the middle labyrinthine layer; (3) the outer, medium electron dense layer. After the formation of the chorion, a vitelline envelope is secreted by the oocyte.
1928年图林描述的颗粒异缓步虫（缓步动物门：高生熊虫科）的卵囊由两层壳组成：薄的卵黄膜和多层的卵壳。卵壳形成过程始于卵黄发生中期。颗粒异缓步虫的卵黄膜属于初级类型（由卵母细胞分泌），但卵壳应被视为混合型：初级（由卵母细胞分泌）和次级（由性腺壁细胞产生）。在卵壳形成早期，卵壳各部分产生，然后连接成一个永久性层。完全发育的卵壳由三层组成：（1）内层，中等电子密度层；（2）中层迷宫层；（3）外层，中等电子密度层。卵壳形成后，卵母细胞分泌卵黄膜。
