Haeckel
Fully grown specimens with 4 latticed concentric shells and many 3-bladed spines of irregular size and distribution. Outermost shell very delicate, thin-walled, with thread-like bars and large, irregular, polygonal meshes; third shell with large, irregular pores and thick bars. Due to its delicacy, the fourth shell is very likely to be absent in sedimentary materials, in which case this species may be identified as Hexalonche aristarchi (see that page). Outermost shell diameter without spines: ca. 220 µm.
Ref.: Haeckel (1887).