Bergquist and Hogg, 1969
Definition: Typically with spherical growth form, with tetraxonid and monaxonid megascleres (triaenes, huge oxeas) in radiate pattern; protriaenes and anatriaenes most common and often protrude from surface; monocrepidial desmas may be present; microscleres contorted microspined sigmaspires, an apomorphy for the group. Reproduction is oviparous without a larval stage, or viviparous with production of young adults within parent. (Cinachyrella apion)
Remarks: A single family (Tetillidae) is traditionally included in this order, but the lithistid family Scleritodermidae also has the apomorphic sigmaspire microsclere and is also best included here. Revision: Rützler (1987).
Source: Hooper's Internet Sponge Guide.
Families represented in the area:
Family Tetillidae: no desmas; with triaenes.
Family Scleritodermidae: lithistid skeleton; no triaenes.