Embryology of the Turbellaria and its phylogenetic significance

  title={Embryology of the Turbellaria and its phylogenetic significance},
  author={Mary Beth Thomas},
Developmental characters — including oocyte and yolk cell structure, patterns of cleavage, and modes of gastrulation — are presented and examined in relation to the phylogeny of the Turbellaria. Eggshell granules, which have been demonstrated to occur in the oocytes of entolecithal eggs and the yolk cells of ectolecithal eggs, are compared among species, and their potential value as a taxonomic character is discussed. The quartet 4d spiral cleavage of the entolecithal egg of polyclads is… CONTINUE READING