Revised description and dimensions:Shell approximately spherical, spongy, denser centrally, of very irregular meshes. Looser outer part generally not present, so that central mass is exposed. Polar spines with central ridge originate from this central area, extend and bifurcate to form a subcircular to subquadrangular ring with distinct indentation proximally. Rarely polar spines not exactly in line so that one part of ring markedly smaller than other part, and very rarely a third spine is present dividing the ring into three approximately equal parts. Ridge of polar spine also bifurcates to join ridge on or near inner edge of ring. Four to fifteen flat spines on ring, varying in size and shape from short, sharp, thornlike to longer, slender, with rounded or sharp ends. Number of spines on each half ring generally unequal; they tend to be concentrated on and near the proximal part of the ring when they are few, and distributed unevenly when more numerous.       (Dimensions and description based on twelve specimens from CAS loc. 39545 [Moreno Grande Formation, East bank of Mitchell Creek, Corral Hollow, Tesla quadrangle, Alameda County, California]). Diameter of shell 85-110µm, of ring (measured along polar spines) 257-97µm, transversely 325-440µm; length of polar spines (from outer spongy surface) 60-90µm.

Remarks:Specimens from UCMP loc. A2615 [Moreno Grande Formation, East bank of Mitchell Creek, Corral Hollow, Tesla quadrangle, Alameda County, California], the type locality, differ from specimens from the other localities mentioned below in their larger size and in having more spines on the ring. A single fragmentary specimen from Trinidad well Marac I differs considerably in having very much thicker polar spines and a much smaller spongy shell, and is not now included in this species.
Stratigraphic range:Early Maestrichtian - Late Maestrichtian. Late Cretaceous. Mesozoic.
Subsequent descriptions:?

Literature cited:- Foreman, H. P. (1968). Upper Maestrichtian Radiolaria of California. The Palaeontological Association, Special Papers in Palaeontology 3: 1-82.