Haeckel, 1879
Diagnosis
Siliceous skeleton lacking, or an individual lattice shell, spherical, ovoid, or variously shaped. With a large mouth. Often with hollow spines with basal pore fields. It is questionable whether all the families placed in this order are closely related. Some should probably be separated into one or more new orders.
Families treated:
Family Atlanticellidae Borgert, 1905
Family Castanellidae Haeckel, 1879
Family Challengeridae Murray, 1876
Family Circoporidae Haeckel, 1887
Family Lirellidae Ehrenberg, 1872
Family Medusettidae Haeckel,1887
Family Porospathidae Borgert, 1901
Family Tuscaroridae Haeckel, 1887