Balanoglossus in Mashail Island described it as a worm-like holothurian. The discovery of gill-slits in this animal by Kowalewsky (1865) led to creation of a special class Enteropneusta by Gegenbaur (1870). Bateson (1885) included them in Phylum Chordata. Hyman (1959), however, placed them near Echinodermata and gave Hemichordata a status of an independent phylum. This simple organism shows affinities with several diverse groups. Balanoglossus is a tuberculos or burrowing and exclusively marine animal. It is found in shallow waters between tide marks along the coast of warm and temperate oceans. Balanoglossus clavigerus is a U-shaped excavated in a sandy bottom Nemertines
Nephridium In freshwater crustacea, the saccate metanephridia are especially large because they are involved in osmoregulation. They have to remove large amounts of water from the tissues, as the crustacean's tissues are hypertonic to the surrounding water. A protonephridium ("proto" = "first") is a network of dead-end tubules lacking internal openings found in the phyla Platyhelminthes, Nemertea, Rotifera and Chordata (lancelets). The ends are called "flame cells" (if ciliated) or "solenocytes" (if flagellated); they function in osmoregulation and ionoregulation, respectively. The terminal cells are located at the blind end of the protonephridium. Each cell has one or more cilia and their