Literature
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- Burdon-Jones, C. 1957. Hemichordata. Enteropneusta, Family Ptychoderidae. Tornaria larvae. Fiches d'Identification du Zooplancton, 70 (.
- Hayward, P.J. and J.S. Ryland 1995. Handbook of the Marine Fauna of North-West Europe. Oxford University Press, Oxford. 800pp.
- Todd, C.D. and M.S. Laverack 1991. Coastal marine zooplankton: A practical manual for students. Cambridge University Press, Cambridge. 106 pp.