ARENOSIPHON Grubbs, 1939
Type species: Arenosiphon giganteus Grubbs, 1939; OD.
Arenosiphon Grubbs. 1939 (*1322), p. 544.
Test free, tubular, elongate, tapering, up to 14 mm in length and 1.0 mm in diameter, straight to slightly curved; wall of agglutinated medium to fine quartz grains, firmly cemented, surface roughly finished. U. Ordovician (Caradocian); glacial pebble, Baltic area; M. Silurian: USA: Illinois.