``The terms "gastrula" and "gastrulation" were coined by Ernst Haeckel, in his 1872 work "Biology of Calcareous Sponges". Lewis Wolpert, pioneering developmental biologist in the field, has been credited for noting that "It is not birth, marriage, or death, but gastrulation which is truly the most important time in your life."''

``It may be doubted if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures.''