Order Halichondrida Gray, 1867. Pp. 721-723. In: Hooper, JN.A. & Van Soest, R.W.M. (eds) Systema Porifera. Guide to the classification of sponges. 2 volumes. Kluwer Academic/ Plenum Publishers: New York, 1708 + xlviii. ISBN 0-306-47260-0 (printed version) - Van Soest, R.W.M.; Hooper, J.N.A. (2002)
The PDF supplied here is a proof - NOT the definitive printed text - of a chapter of the Systema Porifera