敏捷瘦体虫(Urosomoida agiliformis FOISSNER,1982)无性生殖期间的形态发生研究(原生动物,纤毛虫)

敏捷瘦体虫（UrosomoidaagiliformisFOISSNER，1982）为小型腹毛目纤毛虫。利用银染法对该种二分裂期间的形态发生学进行初步研究，指出该虫形态发生的主要过程为：1．伴随大核改组带的出现，口原基发生于老口围带的下方，后演化为后仔虫的口围带。在前仔虫，老口围带及口侧膜完全保留并被继承；2．体棘毛场首先出现后一组棘毛原基，后形成前棘毛场，随后各自独立演化成前后仔虫的8：3／4：2／3模式的额-腹-横棘毛；3．在背触毛中，分别于前、后仔虫的中部产生前、后3列新原基，每列原基向其两端伸展替代老背触毛列，成为前、后仔虫相应的3列新触毛；接着，在右缘棘毛原基右前端发生前、后第4列背触毛。

STUDIES ON THE MORPHOGENESIS OF UROSOMOIDA AGILIFORMIS (PROTOZOA,CILIOPHORA)

A population of the hypotrichous ciliate Urosomoida agildermis Foissner, 1982 was found from a soil sample in Qingdao in 1986. Based on the protargol impregnation method, its morphogenesis was reinvestigated. The overall pattern of the morphogenetic events is similar to that known from most other oxytrichids. 1) It starts with a proliferation of basal bodies for the oral primordium close to the 3 posterior ventral cirri. 2) The 5 anlagen of the frontoventral cirri of the proter and the opisthe are of different origins and evolve separately. 3) In both daughter cells 5 anlagen generate 2, 2, 3 f 3-4, 3-4 frontoventral and transverse cirri. 4 ) The development of the dorsal kineties shows no special features, 3 kineties derive from 3 anlagen, the rightmost one comes from the anlage anterior to the right marginal row.A comparison with the morphogenesis of other species of the genera, e. g.Oxytricha or Steinia shows that the morphogenetic details (e. g. the site of the origin of the oral primordium, the origin of the frontoventral cirri, the mode of development of the dorsal kineties) are very similar and thus suggests a close relationship among those genera.