Close Window
Figure 1   Arrangement of the major gastropod taxa according to the stage at which the mesentoblast is specified. (Formation of the polar lobe has been disregarded.) The more primitive Polyplacophorans are used as an outlier group, and their specification of the mesentoblast takes longer than any of the gastropods. When more than one species has been observed, the range is recorded. Polar lobe formation is indicated by the lack of cell boundaries. (After Van den Bigelaar and Haszprunar 1996.)
Figure 1
Close Window