Fig. 8

Summary of cytoplasmic perturbations described in different polyclad flatworm species. a Depressions of the animal pole during the formation of the first polar body as described by Kato [35] for some Japanese polyclad species and observed for Maritigrella crozieri (this study) are shown. b Cell blebbing depicted in oocytes as described for most polyclads during the first and second meiotic divisions (see [19]. c Vegetal lobe like structures are shown found in Pseudostylochus intermedius [72] and Pseudoceros japonicus [48]. Schematic drawing was taken from P. intermedius. d Cytoplasmic perturbations as seen in Pseudostylochus intermedius (8- to 16-cell stage) [72] and M. crozieri (16- to 32-cell stage, this study). e Waves of contractile activity in all four macromeres of M. crozieri (this study) whereby macromeres attain an elongated shape. f Similar cytoplasmic perturbations seen during the highly asymmetric cleavage of micromere 4d found in M. crozieri (this study)