Article: Corallum increase in Lithostrotion

Serial section examination of increase in ten species of Lithostrotion from Australia and Great Britain has shown that increase is a valuable specific character, and has confirmed earlier reports that in Lithostrotion it is mainly lateral; axial increase has already been reported in Lithostrotion from Russia and peripheral increase is herein described in a specimen from Australia.Four types of lateral increase in Lithostrotion are recognized: (1) increase in L. junceum (Fleming) in which the daughter corallite has an early aseptate stage after which septa are inserted independently of the septa of the parent; (2) increase in fasciculate species with a narrow dissepimentarium, in which the septa of the daughter are independently inserted; (3) increase in fasciculate species with a wide dissepimentarium, in which the initial septa of the daughter corallite are inherited from the parent; (4) increase in cerioid species, which is related to that in fasciculate species with a wide dissepimentarium.