Williamicyathus A. ZHURAVLEV, 1987
Specimen-type: Syringocnema colvillensis holotype, GREGGS, 1959, pl. 13, fig. 6
Systematics:
Order: ARCHAEOCYATHIDA Okulitch, 1935
Suborder: SYRINGOCNEMINA Okulitch, 1935
Superfamily: SYRINGOCNEMOIDEA Taylor, 1910
Family: SYRINGOCNEMIDAE Taylor, 1910