Phylum: Rhombozoa
...Also known as Dicyemida rhombozoa is a phylum of small parasites that live inside the kidneys of cephalopods. Dicyemids exist in two forms, asexual and sexual, juveniles tend to be asexual and adults tend to be sexual. Asexual individuals (called nematogens) produce vermiform larvae within the axial cell. These larvae mature to form more nematogens which will reproduce and fill the kidney. As the larvae age (or the nematogens reach a certain density) they will mature to form rhombogens (the sexual stage). Rhombogens contain gonads (called infusorigens) these infusorigens self-fertilize to produce infusoriform larvae. These larvae are distinct in that they swim around with cilliated rings that look like headlights. These larvae ultimately get released when the host eliminates urine from the kidneys, it is thought that these larvae are both the dispersal and the infectious stage. However the method of infection remains unknown, as are the effects of dicyemids on their hosts.
Phylogeny
Animalia-(mesozoa)-Rhombozoa
Images: Chelsealwood and I.Livingstone