What is "fusulinidae"

The Fusulinidae is a family of fusulinacean Foraminifera from the upper Carboniferous (Lower Pennsylvanian, Morrowan) to the Upper Permian (Guadalupian), tests of which are fusiform to subcylindrical with walls of two to four layers. Are planispirally coiled throughout or with early whorls at a distinct angle to the later plane of coiling. Septa, flat to well fluted; tunnel, single; chomata variable in development.