E. B.  Cutler, The Sipuncula. Their systematics, biology and evolution. Ithaca, N.Y.: Cornell University Press, 1994, p. 453 pp.

M. E.  Rice, ?Larval development and metamorphosis in Sipuncula?, American Zoologist, vol. 16, pp. 563-571, 1976.

M. E.  Rice, ?Larval development and metamorphosis in Sipuncula?, American Zoologist, vol. 16, pp. 563-571, 1976.