Haeckel, 1862
Skeleton consisting of 20 radial spicules of different shape and different length, among which two equatorial spicules are longer and stronger than other 18, each of two main spicules with cornet. Spicules pierce thick, ellipsoidal, armored shell. Around each spicule on upper part of shell are two oval aspinal pores surrounded by five to six sutural pores. Cornets striated longitudinally and serrate at edge. Endoplasm with nuclei, lipid inclusions, and zooxanthellae. Axopods pass across sutural pores. Periplasmic cortex suspended from apex of small spicules by 6-12 myonemes:
One genus: Diploconus
Five species:
Diploconus cyathiscus
Diploconus cylindrus
Diploconus fasces
Diploconus hexaphyllus
Diploconus saturnus