[Morphogenesis of the anterior limb primordium and its histochemical aspects in the pleurodele and the axolotl].

In both species, the primary mesodermal blastema of the forelimb bud derives from a regional proliferation of somatopleural cells under the ectoderm. A cellular sheet of somitic origin invades the limb blastema early. Morphological and histochemical changes suggest the establishment of early ecto-mesodermal interactions in the young limb bud.