Haeckel
Tubes of variable length are present on some of the pores, tube walls are imperforate. Shell diameter: 80-120 µm. According to Strelkov and Reshetnjak (1971) Siphonosphaera socialis Haeckel has usually smaller shells (50-80 µm).
Ref.: Nigrini and Moore (1979), Boltovskoy and Riedel (1980).