The genus Volborthella is removed from synonymy under Salterella and placed in the extinct phylum Agmata. Volborthella is more restricted geographically and occurs in older Lower Cambrian strata than Salterella, but distinguishing younger specimens of that genus from poorly preserved Salterella is difficult. Vologinella is not related to Volborthella or other Agmata. Other genera assigned to the phylum by various workers are discussed, but their assignment to this phylum is either enigmatic or rejected. The published concept that specimens of Volborthella and Salterella are agglutinated sclerites or spines on a larger soft-bodied organism is discussed. The material on which this notion is based is re-illustrated and the notion rejected in favor of the view that these conical forms are the hard parts of discrete organisms.