Rhombozoans: Rhombozoa

In both the wormlike phase and as specialized embryos, rhombozoans swim by movement of the hairlike fibers on their bodies. Scientists do not know how the specialized embryos infect a new host and develop into wormlike rhombozoans. Wormlike embryos develop asexually from a cell of a parent and grow into adults. Asexual (ay-SEK-shuh-wuhl) reproduction is that which takes place without the uniting of egg and sperm for the transfer of DNA from two parents. Crowding of rhombozoans in a host's kidney can cause a shift from asexual to sexual reproduction. When crowding occurs, rhombozoans develop a sex organ that contains both eggs and sperm. The mature sperm unite with eggs, and the fertilized (FUR-teh-lyzed) eggs develop into the specialized form of embryos.