This small fossil is sometimes called a bosuichu, because of its fusiform (bosui) shaped shell. The fusulinid can be categorized by observing its cross section under a microscope. They thrived in shallow seas in tropical and subtropical waters about 300 million years ago, and are yielded in abundance on the Akiyoshidai Plateau in Yamaguchi Prefecture. In Kitakyushu, they can be also found in limestone gravel thought to have been brought from the Hiraodai Plateau.