Figure 8. A 5-shelled (5 spherical concentric shells) polycystine undergoes several growth stages before reaching the adult stage, starting with the small internal sphere, and ending with the full grown 5-shelled specimen. Upon death this skeleton sinks to the sea floor and starts dissolving slowly; because the internal spheres are usually thinner than the external ones, they disappear first. Inadequate taxonomic frameworks and ignorance of these processes are responsible for the erection of many "new species" on the basis of these incomplete skeletons.