Izvestiya of Saratov University.
ISSN 1819-7663 (Print)
ISSN 2542-1921 (Online)

transitory level

Module Organization in the Late Cretaceous Hexactinellids (Hexactinellida, Porifera)

Knowledge on the regularities of vegetative propagation and comprehension of the osculum (oscula) and subosculum structural-functional positions and interrelations in the skeleton structure have made it possible to specify the organization levels in the Late Cretaceous hexactinellids: the unitary (solitary, perifrontal and autonomous forms), transitory (solitary, autonomous and colonial forms) and colonial (primary and true colonies) ones.