Drozdovskiĭ Z M
Arkh Anat Gistol Embriol. 1977 Sep;73(9):88-94.
The figure of tetrahedron is formed in certain species of Plectus and in Tobrilus gracilis at the stage of 4 blastomeres rather than a rhombus which is formed in most highly organized nematodes. The analysis of the Nematoda's embryogenesis allows to conclude that tetrahedron, rhombus as well as some other figures play the role of preblastula sustaining the most expedient disposition of the first blastomers for transition to the formation of the blastula. With the increasing organization of nematodas the tetrahedron preblastula turns into a rhombic, linear-rhombic and at last in aphelenchoid-tylenchoid one. The character of the distribution of structural elements of organs and tissues of the definitive animal in the cytoplasm of the egg of Plectus and Tobrilus confirms the rightness of the division of the class of nematodas into subclasses Enoplia and Chromadoria rather than subclasses Adenophorea and Secernentea.
在某些盘咽线虫属物种以及纤细锥齿线虫的4细胞期形成的是四面体形态，而不是大多数高等组织线虫所形成的菱形。对线虫胚胎发育的分析表明，四面体、菱形以及其他一些形态起着囊胚前期的作用，维持着第一批卵裂球最有利的排列方式，以便过渡到囊胚的形成。随着线虫组织程度的增加，四面体囊胚前期会变成菱形、线性菱形，最后变成滑刃 - 垫刃型。盘咽线虫属和纤细锥齿线虫卵细胞质中终末动物器官和组织结构元素的分布特征，证实了将线虫纲分为无尾感器亚纲和色矛亚纲，而不是腺纲和尾感器亚纲的正确性。
