Vacelet, J.; Borojevic, R.; Boury-Esnault, N.; Manuel, M. (2002). Order Lithonida Vacelet, 1981, Recent. Pp. 1185-1192. In: Hooper, J.N.A. & Van Soest, R.W.M. (eds) Systema Porifera. A guide to the classification of sponges. (2 volumes) Kluwer Academic/ Plenum Publishers: New York, 1708 + xlviii. ISBN 0-36-47260-0 (printed version).
Vacelet, J.; Borojevic, R.; Boury-Esnault, N.; Manuel, M.
2002
Order Lithonida Vacelet, 1981, Recent. Pp. 1185-1192. <i>In</i>: Hooper, J.N.A. & Van Soest, R.W.M. (eds)<i> Systema Porifera. A guide to the classification of sponges</i>. (2 volumes) Kluwer Academic/ Plenum Publishers: New York, 1708 + xlviii
ISBN 0-36-47260-0 (printed version)
Publication
The PDF supplied here is a proof - NOT the definitive printed text - of a chapter of the Systema Porifera
Recent Lithonida (Calcarea, Calcaronea) contains two families of Calcaronea characterized by a hypercalcified skeleton, which is reinforced either by the linkage of tetractines or by the formation of a rigid basal mass of calcite. The living tissue has free calcareous spicules, most frequently including tuning-fork triactines, or diapasons. They appear as survivors of fossil ‘pharetronids’, a polyphyletic grouping of fossil calcareous sponges, and are presently restricted to submarine caves and to bathyal rocky environments. The fossil genera are not treated here.
