Star ascidian  (Botryllus schlosseri)

Asexual reproduction: reproduction that does not involve the formation of sex cells (‘gametes’). In many species, asexual reproduction can occur by fission (or in plants ‘vegetative reproduction’); part of the organism breaks away and develops into a separate individual. Some animals, including vertebrates can develop from unfertilised eggs, this process, known as parthenogenesis gives rise to offspring that are genetically identical to the parent.
Budding: type of asexual reproduction (reproduction that does not involve the formation of sex cells), in which new individuals develop from the parent organism, forming a swelling similar in appearance to a bud. The ‘bud’ slowly separates from the parent as it grows.
Colonial: relating to or belonging to a colony (a group of organisms living together in a group).
Hermaphrodite: possessing both male and female sex organs.
Larval: of the stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
Pharynx: the tube connecting the mouth to the internal body cavity where digestion occurs. In vertebrates, the part of the gut between the mouth and the oesophagus.
Plankton: aquatic organisms that drift with water movements; may be either phytoplankton (plants), or zooplankton (animals).
Zooid: an individual colony member of colonial invertebrates, such as bryozoans.

1. National Biodiversity Network Species Dictionary (January 2003):
   http://www.nhm.ac.uk/nbn
   
2. Hiscock, K., (2001) Botryllus schlosseri. Star ascidian. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth:Marine Biological Association of the United Kingdom. [cited 27/11/02].
   http://www.marlin.ac.uk/species/Botryllusschlosseri.htm
   
3. Fish, J. D. & Fish, S. (1996) A student's guide to the seashore. Second Edition. Cambridge University Press, Cambridge.