Volborthellida Agmata is a proposed extinct phylum of small animals with a calcareous conical shell.

The grains may be of quartz or calcium carbonate, but are of specific shapes and materials that are rare in the surrounding rock.

Though the body of the living animal is not preserved, it had to be able to find, choose, and retrieve rare grains from its environment to build the laminae.

[2] The poorly known Middle Cambrian fossil Vologdinella was also considered for inclusion, as it has superficial resemblance to the Agmata, but was later excluded from the group.

Attempts to reconcile these genera as members of any other group have been rejected due to basic differences in structure, but not all paleontologists accept them as a phylum; Jones (2007) considers the shell an agglutinating test parallel to that of foraminifers.