Characters of the female gonad and the phylogeny of Platyhelminthes

The female gonad of Platyhelminthes shows a wide variability in its anatomi cal and cellular organization and submicroscopic structure, and some charac teristics may be useful for elucidating the questioned monophyly of some ta xa and reconstructing the phylogenetic tree of the group. The morphological characters of the female gonad have been subdivided into three levels: mac roscopic, microscopic and ultrastructural, and some examples with potential phylogenetic value are presented for each level.