Follicucullus属放散虫の新種記載

One of an important index for the late Middle to early Late Permian, ' species of Follicucullus Ormiston and Babcock is reexamined in view point of stratigraphic occurrence,biogeographic distribution and morphology. Japanese Follicucullus which has been regarded to be F. ventricosus Ormiston and Babcock or treated as Follicucullus scholasticus Ormiston and Babcock morphotype II of Ishiga is described as a new species of Follicucullus. Evolutional trend of Follicucullus is discussed and a new lineage zone of Follicucullus is proposed.