ABSTRACT
This chapter deals with the ascidians of the Indian Ocean with emphasis on their biology and taxonomy. Ascidians are considered as one of the important fouling organisms. They are recorded from ships, test panels, cables, buoys, and harbor installations throughout the world. The colonial sessile ascidians are found attached in great numbers to the surfaces of stones, rocks, pilings, piers, ship bottoms and even to algae. Asexual reproduction in the colonial ascidian takes place by budding through post-abdominal strobilation. Fertilization is internal and takes place in either the ovary or the oviduct since early embryos are commonly found in the terminal portion of the oviduct. Metamorphosis of the free-swimming tadpole larvae is a cardinal event in the life cycle of all ascidians, with the exception of a few anurous species belonging to the families Molgulidae and Styelidae, which have direct development.
