[Evolutionary reorganizations of ontogenesis in ascidians of the genus Molgula].

The data on comparative, experimental, and molecular embryology of ascidians (genus Molgula) published during the last 15 years have been reviewed. Some representatives of this genus evolved from development with a tailed larva (tadpole) to direct development associated with the loss of larval structures, such as tail, notochord, sensory organs, and differentiated muscles. The data on evolutionary reorganizations of ontogenesis in ascidians of the genus Molgula have been compared with those in sea urchins, anuran amphibians, and some other organisms.