Systematic descriptions

Abstract

Diagnosis (freely translated from Vacelet, 1959). - Like the closely related Hippospongia, Spongia comprises keratose sponges in which the fiber reticulation is highly developed. The primary fibers are rare and most often contain some foreign particles. The stratification of spongin is not readily observed, either in primary or secondary fibers. The latter are always devoid of foreign inclusions, and form a dense, very supple, elastic reticulation, hence the domestic properties of these sponges. The flagellate chambers are typical of the Spongiidae, small and spherical. The habit is generally massive, but may be more differentiated in some species and varieties: incrusting, laminar, caliculate, ramose, etc. The dermis is thin, rarely sandy.