Prospect of changes in such umbilical structures as Lip, Portici and Tegilla throughout Turonian-Campanian was also investigated. The phylogenic trend show that Lip structure in primary morphogroups turns gradually to tegilla in more developed forms in which the opening become also entirely umbilical. Statistical an analysis showed that the trends of changes are correlatable with increase in water depth while a decrease in depth result in development of lip in the planktonic foraminifera studied. The changes are considered to be in accord with Pascal law
