With Carl Gegenbaur and Ernst Haeckel, inspiredby Darwin and the cell theory, comparativeanatomy and embryology became established andflourished in Jena. This tradition wascontinued and developed further with new ideasand methods devised by some of Haeckelsstudents. This first period of innovative workin evolutionary morphology was followed byperiods of crisis and even a disintegration ofthe discipline in the early twentieth century.This stagnation was caused by a lack ofinterest among morphologists in Mendeliangenetics, and uncertainty about the mechanismsof evolution. Idealistic morphology was stillinfluental in (...) Germany, which prevented a fullappreciation of the importance of Darwinstheory of natural selection for comparativemorphology. Evolutionary morphology andembryology failed to contribute significantlyto the modern synthesis of evolutionarybiology, thereby probably delaying theintegration of developmental biology intomodern evolutionary biology. However, Haeckelsstudent Oscar Hertwig, as well as Victor Franzand Alexej N. Sewertzoff from a youngergeneration, all tried to forge their ownsynthetic approaches in which (inspired byHaeckels work) embryology played an importantrole. Important for all three researchers wereattempts to refine, and sometimes redefine, thebiogenetic law, and to find new scientificexplanations for it (and for the manyexceptions to it). Their research was latermore or less forgotten, and had littleinfluence on the architects of the modernsynthesis. As the relationship betweenevolutionary and developmental biology is nowagain rising in importance in the form ofEvo-Devo, we would like to draw attention tohow this earlier research tradition grappledwith similar questions to those now on theagenda, albeit from sometimes quite differentperspectives. (shrink)